diff --git a/dom/base/nsDOMClassInfo.h b/dom/base/nsDOMClassInfo.h
index 34d9c2eda858..0d37e7e7314a 100644
--- a/dom/base/nsDOMClassInfo.h
+++ b/dom/base/nsDOMClassInfo.h
@@ -7,6 +7,7 @@
 #ifndef nsDOMClassInfo_h___
 #define nsDOMClassInfo_h___
 
+#include "mozilla/Attributes.h"
 #include "nsIDOMClassInfo.h"
 #include "nsIXPCScriptable.h"
 #include "jsapi.h"
@@ -139,11 +140,11 @@ protected:
 
   const nsDOMClassInfoData* mData;
 
-  virtual void PreserveWrapper(nsISupports *aNative)
+  virtual void PreserveWrapper(nsISupports *aNative) MOZ_OVERRIDE
   {
   }
 
-  virtual uint32_t GetInterfacesBitmap()
+  virtual uint32_t GetInterfacesBitmap() MOZ_OVERRIDE
   {
     return mData->mInterfacesBitmap;
   }
@@ -285,11 +286,11 @@ protected:
   }
 public:
   NS_IMETHOD PreCreate(nsISupports *nativeObj, JSContext *cx,
-                       JSObject *globalObj, JSObject **parentObj);
+                       JSObject *globalObj, JSObject **parentObj) MOZ_OVERRIDE;
   NS_IMETHOD AddProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                         JSObject *obj, jsid id, jsval *vp, bool *_retval);
+                         JSObject *obj, jsid id, jsval *vp, bool *_retval) MOZ_OVERRIDE;
 
-  virtual void PreserveWrapper(nsISupports *aNative);
+  virtual void PreserveWrapper(nsISupports *aNative) MOZ_OVERRIDE;
 
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
   {
@@ -310,11 +311,11 @@ protected:
   }
 public:
   NS_IMETHOD PreCreate(nsISupports* aNativeObj, JSContext* aCx,
-                       JSObject* aGlobalObj, JSObject** aParentObj);
+                       JSObject* aGlobalObj, JSObject** aParentObj) MOZ_OVERRIDE;
   NS_IMETHOD AddProperty(nsIXPConnectWrappedNative* aWrapper, JSContext* aCx,
-                         JSObject* aObj, jsid Id, jsval* aVp, bool* aRetval);
+                         JSObject* aObj, jsid Id, jsval* aVp, bool* aRetval) MOZ_OVERRIDE;
 
-  virtual void PreserveWrapper(nsISupports *aNative);
+  virtual void PreserveWrapper(nsISupports *aNative) MOZ_OVERRIDE;
 
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
   {
@@ -341,10 +342,10 @@ protected:
 
 public:
   NS_IMETHOD PreCreate(nsISupports *nativeObj, JSContext *cx,
-                       JSObject *globalObj, JSObject **parentObj);
+                       JSObject *globalObj, JSObject **parentObj) MOZ_OVERRIDE;
 #ifdef DEBUG
   NS_IMETHOD PostCreate(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                        JSObject *obj)
+                        JSObject *obj) MOZ_OVERRIDE
   {
     nsCOMPtr<nsIScriptGlobalObject> sgo(do_QueryWrappedNative(wrapper));
 
@@ -353,21 +354,21 @@ public:
 
     return NS_OK;
   }
-  virtual uint32_t GetScriptableFlags()
+  virtual uint32_t GetScriptableFlags() MOZ_OVERRIDE
   {
     return nsDOMGenericSH::GetScriptableFlags() |
            nsIXPCScriptable::WANT_POSTCREATE;
   }
 #endif
   NS_IMETHOD Enumerate(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                       JSObject *obj, bool *_retval);
+                       JSObject *obj, bool *_retval) MOZ_OVERRIDE;
   NS_IMETHOD NewResolve(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                         JSObject *obj, jsid id, uint32_t flags,
-                        JSObject **objp, bool *_retval);
+                        JSObject **objp, bool *_retval) MOZ_OVERRIDE;
   NS_IMETHOD Finalize(nsIXPConnectWrappedNative *wrapper, JSFreeOp *fop,
-                      JSObject *obj);
+                      JSObject *obj) MOZ_OVERRIDE;
   NS_IMETHOD OuterObject(nsIXPConnectWrappedNative *wrapper, JSContext * cx,
-                         JSObject * obj, JSObject * *_retval);
+                         JSObject * obj, JSObject * *_retval) MOZ_OVERRIDE;
 
   static JSBool GlobalScopePolluterNewResolve(JSContext *cx, JSHandleObject obj,
                                               JSHandleId id, unsigned flags,
@@ -400,10 +401,10 @@ protected:
 public:
   NS_IMETHOD CheckAccess(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                          JSObject *obj, jsid id, uint32_t mode,
-                         jsval *vp, bool *_retval);
+                         jsval *vp, bool *_retval) MOZ_OVERRIDE;
 
   NS_IMETHOD PreCreate(nsISupports *nativeObj, JSContext *cx,
-                       JSObject *globalObj, JSObject **parentObj);
+                       JSObject *globalObj, JSObject **parentObj) MOZ_OVERRIDE;
   NS_IMETHODIMP AddProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                             JSObject *obj, jsid id, jsval *vp, bool *_retval);
 
@@ -429,10 +430,10 @@ protected:
 
 public:
   NS_IMETHOD PreCreate(nsISupports *nativeObj, JSContext *cx,
-                       JSObject *globalObj, JSObject **parentObj);
+                       JSObject *globalObj, JSObject **parentObj) MOZ_OVERRIDE;
   NS_IMETHOD NewResolve(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                         JSObject *obj, jsid id, uint32_t flags,
-                        JSObject **objp, bool *_retval);
+                        JSObject **objp, bool *_retval) MOZ_OVERRIDE;
 
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
   {
@@ -456,15 +457,15 @@ protected:
 
 public:
   NS_IMETHOD PreCreate(nsISupports *nativeObj, JSContext *cx,
-                       JSObject *globalObj, JSObject **parentObj);
+                       JSObject *globalObj, JSObject **parentObj) MOZ_OVERRIDE;
   NS_IMETHOD AddProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                         JSObject *obj, jsid id, jsval *vp, bool *_retval);
+                         JSObject *obj, jsid id, jsval *vp, bool *_retval) MOZ_OVERRIDE;
   NS_IMETHOD NewResolve(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                         JSObject *obj, jsid id, uint32_t flags,
-                        JSObject **objp, bool *_retval);
-  NS_IMETHOD GetFlags(uint32_t *aFlags);
+                        JSObject **objp, bool *_retval) MOZ_OVERRIDE;
+  NS_IMETHOD GetFlags(uint32_t *aFlags) MOZ_OVERRIDE;
 
-  virtual void PreserveWrapper(nsISupports *aNative);
+  virtual void PreserveWrapper(nsISupports *aNative) MOZ_OVERRIDE;
 
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
   {
@@ -488,11 +489,11 @@ protected:
 
 public:
   NS_IMETHOD PreCreate(nsISupports *nativeObj, JSContext *cx,
-                       JSObject *globalObj, JSObject **parentObj);
+                       JSObject *globalObj, JSObject **parentObj) MOZ_OVERRIDE;
   NS_IMETHOD PostCreate(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                        JSObject *obj);
+                        JSObject *obj) MOZ_OVERRIDE;
   NS_IMETHOD PostTransplant(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                            JSObject *obj);
+                            JSObject *obj) MOZ_OVERRIDE;
 
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
   {
@@ -517,9 +518,9 @@ protected:
 public:
   NS_IMETHOD NewResolve(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                         JSObject *obj, jsid id, uint32_t flags,
-                        JSObject **objp, bool *_retval);
+                        JSObject **objp, bool *_retval) MOZ_OVERRIDE;
   NS_IMETHOD Enumerate(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                       JSObject *obj, bool *_retval);
+                       JSObject *obj, bool *_retval) MOZ_OVERRIDE;
   
   virtual nsresult GetLength(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                              JSObject *obj, uint32_t *length);
@@ -551,7 +552,7 @@ protected:
 
 public:
   NS_IMETHOD GetProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                         JSObject *obj, jsid id, jsval *vp, bool *_retval);
+                         JSObject *obj, jsid id, jsval *vp, bool *_retval) MOZ_OVERRIDE;
 
 private:
   // Not implemented, nothing should create an instance of this class.
@@ -574,7 +575,7 @@ protected:
 
   NS_IMETHOD NewResolve(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                         JSObject *obj, jsid id, uint32_t flags,
-                        JSObject **objp, bool *_retval);
+                        JSObject **objp, bool *_retval) MOZ_OVERRIDE;
 
   virtual nsISupports* GetNamedItem(nsISupports *aNative,
                                     const nsAString& aName,
@@ -583,7 +584,7 @@ protected:
 
 public:
   NS_IMETHOD GetProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                         JSObject *obj, jsid id, jsval *vp, bool *_retval);
+                         JSObject *obj, jsid id, jsval *vp, bool *_retval) MOZ_OVERRIDE;
 
 private:
   // Not implemented, nothing should create an instance of this class.
@@ -633,15 +634,15 @@ protected:
 public:
   NS_IMETHOD NewResolve(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                         JSObject *obj, jsid id, uint32_t flags,
-                        JSObject **objp, bool *_retval);
+                        JSObject **objp, bool *_retval) MOZ_OVERRIDE;
   NS_IMETHOD GetProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                          JSObject *obj, jsid id, jsval *vp,
-                         bool *_retval);
+                         bool *_retval) MOZ_OVERRIDE;
 
   NS_IMETHOD NewEnumerate(nsIXPConnectWrappedNative *wrapper,
                           JSContext *cx, JSObject *obj,
                           uint32_t enum_op, jsval *statep,
-                          jsid *idp, bool *_retval);
+                          jsid *idp, bool *_retval) MOZ_OVERRIDE;
 
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
   {
@@ -664,13 +665,13 @@ protected:
   }
 
   virtual nsISupports* GetItemAt(nsISupports *aNative, uint32_t aIndex,
-                                 nsWrapperCache **aCache, nsresult *aResult);
+                                 nsWrapperCache **aCache, nsresult *aResult) MOZ_OVERRIDE;
 
   // Override nsNamedArraySH::GetNamedItem()
   virtual nsISupports* GetNamedItem(nsISupports *aNative,
                                     const nsAString& aName,
                                     nsWrapperCache **cache,
-                                    nsresult *aResult);
+                                    nsresult *aResult) MOZ_OVERRIDE;
 
 public:
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
@@ -694,13 +695,13 @@ protected:
   }
 
   virtual nsISupports* GetItemAt(nsISupports *aNative, uint32_t aIndex,
-                                 nsWrapperCache **aCache, nsresult *aResult);
+                                 nsWrapperCache **aCache, nsresult *aResult) MOZ_OVERRIDE;
 
   // Override nsNamedArraySH::GetNamedItem()
   virtual nsISupports* GetNamedItem(nsISupports *aNative,
                                     const nsAString& aName,
                                     nsWrapperCache **cache,
-                                    nsresult *aResult);
+                                    nsresult *aResult) MOZ_OVERRIDE;
 
 public:
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
@@ -724,13 +725,13 @@ protected:
   }
 
   virtual nsISupports* GetItemAt(nsISupports *aNative, uint32_t aIndex,
-                                 nsWrapperCache **aCache, nsresult *aResult);
+                                 nsWrapperCache **aCache, nsresult *aResult) MOZ_OVERRIDE;
 
   // Override nsNamedArraySH::GetNamedItem()
   virtual nsISupports* GetNamedItem(nsISupports *aNative,
                                     const nsAString& aName,
                                     nsWrapperCache **cache,
-                                    nsresult *aResult);
+                                    nsresult *aResult) MOZ_OVERRIDE;
 
 public:
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
@@ -758,7 +759,7 @@ protected:
 
 public:
   NS_IMETHOD GetProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                         JSObject *obj, jsid id, jsval *vp, bool *_retval);
+                         JSObject *obj, jsid id, jsval *vp, bool *_retval) MOZ_OVERRIDE;
 };
 
 
@@ -776,13 +777,13 @@ protected:
   }
 
   virtual nsresult GetStringAt(nsISupports *aNative, int32_t aIndex,
-                               nsAString& aResult);
+                               nsAString& aResult) MOZ_OVERRIDE;
 
 public:
   NS_IMETHOD PreCreate(nsISupports *nativeObj, JSContext *cx,
-                       JSObject *globalObj, JSObject **parentObj);
+                       JSObject *globalObj, JSObject **parentObj) MOZ_OVERRIDE;
   NS_IMETHOD GetProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                         JSObject *obj, jsid id, jsval *vp, bool *_retval);
+                         JSObject *obj, jsid id, jsval *vp, bool *_retval) MOZ_OVERRIDE;
 
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
   {
@@ -804,7 +805,7 @@ protected:
   }
 
   virtual nsresult GetStringAt(nsISupports *aNative, int32_t aIndex,
-                               nsAString& aResult);
+                               nsAString& aResult) MOZ_OVERRIDE;
 
 public:
   // Inherit GetProperty, Enumerate from nsStringArraySH
@@ -830,7 +831,7 @@ protected:
   }
 
   virtual nsresult GetStringAt(nsISupports *aNative, int32_t aIndex,
-                               nsAString& aResult);
+                               nsAString& aResult) MOZ_OVERRIDE;
 
 public:
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
@@ -854,7 +855,7 @@ protected:
   }
 
   virtual nsISupports* GetItemAt(nsISupports *aNative, uint32_t aIndex,
-                                 nsWrapperCache **aCache, nsresult *aResult);
+                                 nsWrapperCache **aCache, nsresult *aResult) MOZ_OVERRIDE;
 
 public:
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
@@ -878,7 +879,7 @@ protected:
   }
 
   virtual nsISupports* GetItemAt(nsISupports *aNative, uint32_t aIndex,
-                                 nsWrapperCache **aCache, nsresult *aResult);
+                                 nsWrapperCache **aCache, nsresult *aResult) MOZ_OVERRIDE;
 
 public:
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
@@ -899,7 +900,7 @@ class nsDOMTouchListSH : public nsArraySH
   }
 
   virtual nsISupports* GetItemAt(nsISupports *aNative, uint32_t aIndex,
-                                 nsWrapperCache **aCache, nsresult *aResult);
+                                 nsWrapperCache **aCache, nsresult *aResult) MOZ_OVERRIDE;
 
   public:
   static nsIClassInfo* doCreate(nsDOMClassInfoData* aData)
@@ -923,16 +924,16 @@ protected:
 
   NS_IMETHOD NewResolve(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                         JSObject *obj, jsid id, uint32_t flags,
-                        JSObject **objp, bool *_retval);
+                        JSObject **objp, bool *_retval) MOZ_OVERRIDE;
   NS_IMETHOD SetProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                         JSObject *obj, jsid id, jsval *vp, bool *_retval);
+                         JSObject *obj, jsid id, jsval *vp, bool *_retval) MOZ_OVERRIDE;
   NS_IMETHOD GetProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                         JSObject *obj, jsid id, jsval *vp, bool *_retval);
+                         JSObject *obj, jsid id, jsval *vp, bool *_retval) MOZ_OVERRIDE;
   NS_IMETHOD DelProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                         JSObject *obj, jsid id, bool *_retval);
+                         JSObject *obj, jsid id, bool *_retval) MOZ_OVERRIDE;
   NS_IMETHOD NewEnumerate(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                           JSObject *obj, uint32_t enum_op, jsval *statep,
-                          jsid *idp, bool *_retval);
+                          jsid *idp, bool *_retval) MOZ_OVERRIDE;
 
 public:
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
@@ -975,19 +976,19 @@ protected:
 
 public:
   NS_IMETHOD PreCreate(nsISupports *nativeObj, JSContext *cx,
-                       JSObject *globalObj, JSObject **parentObj);
-  NS_IMETHOD PostCreatePrototype(JSContext * cx, JSObject * proto)
+                       JSObject *globalObj, JSObject **parentObj) MOZ_OVERRIDE;
+  NS_IMETHOD PostCreatePrototype(JSContext * cx, JSObject * proto) MOZ_OVERRIDE
   {
     return NS_OK;
   }
   NS_IMETHOD NewResolve(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                         JSObject *obj, jsid id, uint32_t flags,
-                        JSObject **objp, bool *_retval);
+                        JSObject **objp, bool *_retval) MOZ_OVERRIDE;
   NS_IMETHOD Call(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                  JSObject *obj, const JS::CallArgs &args, bool *_retval);
+                  JSObject *obj, const JS::CallArgs &args, bool *_retval) MOZ_OVERRIDE;
 
   NS_IMETHOD Construct(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
-                       JSObject *obj, const JS::CallArgs &args, bool *_retval);
+                       JSObject *obj, const JS::CallArgs &args, bool *_retval) MOZ_OVERRIDE;
 
   NS_IMETHOD HasInstance(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
                          JSObject *obj, const jsval &val, bool *bp,
@@ -1011,7 +1012,7 @@ protected:
   }
 
 public:
-  NS_IMETHOD GetFlags(uint32_t *aFlags);
+  NS_IMETHOD GetFlags(uint32_t *aFlags) MOZ_OVERRIDE;
 
   static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
   {
diff --git a/dom/base/nsDOMScriptObjectFactory.h b/dom/base/nsDOMScriptObjectFactory.h
index 46cb8651358d..dd4868c1c527 100644
--- a/dom/base/nsDOMScriptObjectFactory.h
+++ b/dom/base/nsDOMScriptObjectFactory.h
@@ -36,8 +36,8 @@ public:
   NS_DECL_NSIOBSERVER
 
   // nsIDOMScriptObjectFactory
-  NS_IMETHOD_(nsISupports *) GetClassInfoInstance(nsDOMClassInfoID aID);
-  NS_IMETHOD_(nsISupports *) GetExternalClassInfoInstance(const nsAString& aName);
+  NS_IMETHOD_(nsISupports *) GetClassInfoInstance(nsDOMClassInfoID aID) MOZ_OVERRIDE;
+  NS_IMETHOD_(nsISupports *) GetExternalClassInfoInstance(const nsAString& aName) MOZ_OVERRIDE;
 
   NS_IMETHOD RegisterDOMClassInfo(const char *aName,
                                   nsDOMClassInfoExternalConstructorFnc aConstructorFptr,
@@ -45,7 +45,7 @@ public:
                                   const nsIID **aInterfaces,
                                   uint32_t aScriptableFlags,
                                   bool aHasClassInterface,
-                                  const nsCID *aConstructorCID);
+                                  const nsCID *aConstructorCID) MOZ_OVERRIDE;
 };
 
 class nsDOMExceptionProvider MOZ_FINAL : public nsIExceptionProvider
diff --git a/dom/base/nsJSEnvironment.h b/dom/base/nsJSEnvironment.h
index d4679b9af63b..8794374f4928 100644
--- a/dom/base/nsJSEnvironment.h
+++ b/dom/base/nsJSEnvironment.h
@@ -48,7 +48,7 @@ public:
                                   JS::Handle<JSObject*> aScopeObject,
                                   JS::CompileOptions &aOptions,
                                   bool aCoerceToString,
-                                  JS::Value* aRetValue);
+                                  JS::Value* aRetValue) MOZ_OVERRIDE;
 
   virtual nsresult CompileScript(const PRUnichar* aText,
                                  int32_t aTextLength,
@@ -57,46 +57,46 @@ public:
                                  uint32_t aLineNo,
                                  uint32_t aVersion,
                                  JS::MutableHandle<JSScript*> aScriptObject,
-                                 bool aSaveSource = false);
+                                 bool aSaveSource = false) MOZ_OVERRIDE;
   virtual nsresult ExecuteScript(JSScript* aScriptObject,
-                                 JSObject* aScopeObject);
+                                 JSObject* aScopeObject) MOZ_OVERRIDE;
 
   virtual nsresult BindCompiledEventHandler(nsISupports *aTarget,
                                             JS::Handle<JSObject*> aScope,
                                             JS::Handle<JSObject*> aHandler,
-                                            JS::MutableHandle<JSObject*> aBoundHandler);
+                                            JS::MutableHandle<JSObject*> aBoundHandler) MOZ_OVERRIDE;
 
-  virtual nsIScriptGlobalObject *GetGlobalObject();
+  virtual nsIScriptGlobalObject *GetGlobalObject() MOZ_OVERRIDE;
   inline nsIScriptGlobalObject *GetGlobalObjectRef() { return mGlobalObjectRef; }
 
-  virtual JSContext* GetNativeContext();
-  virtual JSObject* GetNativeGlobal();
-  virtual nsresult InitContext();
-  virtual bool IsContextInitialized();
+  virtual JSContext* GetNativeContext() MOZ_OVERRIDE;
+  virtual JSObject* GetNativeGlobal() MOZ_OVERRIDE;
+  virtual nsresult InitContext() MOZ_OVERRIDE;
+  virtual bool IsContextInitialized() MOZ_OVERRIDE;
 
-  virtual void ScriptEvaluated(bool aTerminated);
-  virtual bool GetScriptsEnabled();
-  virtual void SetScriptsEnabled(bool aEnabled, bool aFireTimeouts);
+  virtual void ScriptEvaluated(bool aTerminated) MOZ_OVERRIDE;
+  virtual bool GetScriptsEnabled() MOZ_OVERRIDE;
+  virtual void SetScriptsEnabled(bool aEnabled, bool aFireTimeouts) MOZ_OVERRIDE;
 
-  virtual nsresult SetProperty(JS::Handle<JSObject*> aTarget, const char* aPropName, nsISupports* aVal);
+  virtual nsresult SetProperty(JS::Handle<JSObject*> aTarget, const char* aPropName, nsISupports* aVal) MOZ_OVERRIDE;
 
-  virtual bool GetProcessingScriptTag();
-  virtual void SetProcessingScriptTag(bool aResult);
+  virtual bool GetProcessingScriptTag() MOZ_OVERRIDE;
+  virtual void SetProcessingScriptTag(bool aResult) MOZ_OVERRIDE;
 
-  virtual bool GetExecutingScript();
+  virtual bool GetExecutingScript() MOZ_OVERRIDE;
 
-  virtual nsresult InitClasses(JS::Handle<JSObject*> aGlobalObj);
+  virtual nsresult InitClasses(JS::Handle<JSObject*> aGlobalObj) MOZ_OVERRIDE;
 
-  virtual void WillInitializeContext();
-  virtual void DidInitializeContext();
+  virtual void WillInitializeContext() MOZ_OVERRIDE;
+  virtual void DidInitializeContext() MOZ_OVERRIDE;
 
   virtual nsresult Serialize(nsIObjectOutputStream* aStream,
-                             JS::Handle<JSScript*> aScriptObject);
+                             JS::Handle<JSScript*> aScriptObject) MOZ_OVERRIDE;
   virtual nsresult Deserialize(nsIObjectInputStream* aStream,
-                               JS::MutableHandle<JSScript*> aResult);
+                               JS::MutableHandle<JSScript*> aResult) MOZ_OVERRIDE;
 
-  virtual void EnterModalState();
-  virtual void LeaveModalState();
+  virtual void EnterModalState() MOZ_OVERRIDE;
+  virtual void LeaveModalState() MOZ_OVERRIDE;
 
   NS_DECL_NSIXPCSCRIPTNOTIFY
 
@@ -144,7 +144,7 @@ public:
   // Calling LikelyShortLivingObjectCreated() makes a GC more likely.
   static void LikelyShortLivingObjectCreated();
 
-  virtual void GC(JS::gcreason::Reason aReason);
+  virtual void GC(JS::gcreason::Reason aReason) MOZ_OVERRIDE;
 
   static uint32_t CleanupsSinceLastGC();
 
@@ -223,7 +223,7 @@ public:
 
   virtual already_AddRefed<nsIScriptContext>
   CreateContext(bool aGCOnDestruction,
-                nsIScriptGlobalObject* aGlobalObject);
+                nsIScriptGlobalObject* aGlobalObject) MOZ_OVERRIDE;
 
   static void Startup();
   static void Shutdown();
diff --git a/dom/base/nsWindowRoot.h b/dom/base/nsWindowRoot.h
index fcbc7284a283..0e7b21247677 100644
--- a/dom/base/nsWindowRoot.h
+++ b/dom/base/nsWindowRoot.h
@@ -14,6 +14,7 @@ class nsIDOMEvent;
 class nsEventChainPreVisitor;
 class nsEventChainPostVisitor;
 
+#include "mozilla/Attributes.h"
 #include "nsIDOMEventTarget.h"
 #include "nsEventListenerManager.h"
 #include "nsPIWindowRoot.h"
@@ -36,20 +37,20 @@ public:
 
   // nsPIWindowRoot
 
-  virtual nsPIDOMWindow* GetWindow();
+  virtual nsPIDOMWindow* GetWindow() MOZ_OVERRIDE;
 
-  virtual nsresult GetControllers(nsIControllers** aResult);
+  virtual nsresult GetControllers(nsIControllers** aResult) MOZ_OVERRIDE;
   virtual nsresult GetControllerForCommand(const char * aCommand,
-                                           nsIController** _retval);
+                                           nsIController** _retval) MOZ_OVERRIDE;
 
-  virtual nsIDOMNode* GetPopupNode();
-  virtual void SetPopupNode(nsIDOMNode* aNode);
+  virtual nsIDOMNode* GetPopupNode() MOZ_OVERRIDE;
+  virtual void SetPopupNode(nsIDOMNode* aNode) MOZ_OVERRIDE;
 
-  virtual void SetParentTarget(mozilla::dom::EventTarget* aTarget)
+  virtual void SetParentTarget(mozilla::dom::EventTarget* aTarget) MOZ_OVERRIDE
   {
     mParent = aTarget;
   }
-  virtual mozilla::dom::EventTarget* GetParentTarget() { return mParent; }
+  virtual mozilla::dom::EventTarget* GetParentTarget() MOZ_OVERRIDE { return mParent; }
   virtual nsIDOMWindow* GetOwnerGlobal() MOZ_OVERRIDE;
 
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(nsWindowRoot,
diff --git a/dom/bluetooth/BluetoothAdapter.h b/dom/bluetooth/BluetoothAdapter.h
index 1877b6d6bfed..1246bc4638fd 100644
--- a/dom/bluetooth/BluetoothAdapter.h
+++ b/dom/bluetooth/BluetoothAdapter.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_bluetooth_bluetoothadapter_h__
 #define mozilla_dom_bluetooth_bluetoothadapter_h__
 
+#include "mozilla/Attributes.h"
 #include "BluetoothCommon.h"
 #include "BluetoothPropertyContainer.h"
 #include "nsCOMPtr.h"
@@ -48,7 +49,7 @@ public:
   }
 
   void Unroot();
-  virtual void SetPropertyByValue(const BluetoothNamedValue& aValue);  
+  virtual void SetPropertyByValue(const BluetoothNamedValue& aValue) MOZ_OVERRIDE;  
 private:
 
   BluetoothAdapter(nsPIDOMWindow* aOwner, const BluetoothValue& aValue);
diff --git a/dom/bluetooth/BluetoothDevice.h b/dom/bluetooth/BluetoothDevice.h
index 2474d750ba51..1ea8c3479192 100644
--- a/dom/bluetooth/BluetoothDevice.h
+++ b/dom/bluetooth/BluetoothDevice.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_bluetooth_bluetoothdevice_h__
 #define mozilla_dom_bluetooth_bluetoothdevice_h__
 
+#include "mozilla/Attributes.h"
 #include "BluetoothCommon.h"
 #include "BluetoothPropertyContainer.h"
 #include "nsDOMEventTargetHelper.h"
@@ -48,7 +49,7 @@ public:
     return static_cast<EventTarget*>(this);
   }
 
-  void SetPropertyByValue(const BluetoothNamedValue& aValue);
+  void SetPropertyByValue(const BluetoothNamedValue& aValue) MOZ_OVERRIDE;
 
   void Unroot();
 private:
diff --git a/dom/bluetooth/BluetoothManager.h b/dom/bluetooth/BluetoothManager.h
index dcaf9abb957a..9e67306e8bb2 100644
--- a/dom/bluetooth/BluetoothManager.h
+++ b/dom/bluetooth/BluetoothManager.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_bluetooth_bluetoothmanager_h__
 #define mozilla_dom_bluetooth_bluetoothmanager_h__
 
+#include "mozilla/Attributes.h"
 #include "BluetoothCommon.h"
 #include "BluetoothPropertyContainer.h"
 #include "nsDOMEventTargetHelper.h"
@@ -31,7 +32,7 @@ public:
   static already_AddRefed<BluetoothManager>
   Create(nsPIDOMWindow* aWindow);
   void Notify(const BluetoothSignal& aData);
-  virtual void SetPropertyByValue(const BluetoothNamedValue& aValue);
+  virtual void SetPropertyByValue(const BluetoothNamedValue& aValue) MOZ_OVERRIDE;
 private:
   BluetoothManager(nsPIDOMWindow* aWindow);
   ~BluetoothManager();
diff --git a/dom/bluetooth/BluetoothReplyRunnable.h b/dom/bluetooth/BluetoothReplyRunnable.h
index 6a8cb5615b3c..8124ba94005b 100644
--- a/dom/bluetooth/BluetoothReplyRunnable.h
+++ b/dom/bluetooth/BluetoothReplyRunnable.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_bluetooth_bluetoothreplyrunnable_h__
 #define mozilla_dom_bluetooth_bluetoothreplyrunnable_h__
 
+#include "mozilla/Attributes.h"
 #include "BluetoothCommon.h"
 #include "nsThreadUtils.h"
 #include "jsapi.h"
@@ -58,7 +59,7 @@ public:
  ~BluetoothVoidReplyRunnable();
 
 protected:
-  virtual bool ParseSuccessfulReply(JS::Value* aValue)
+  virtual bool ParseSuccessfulReply(JS::Value* aValue) MOZ_OVERRIDE
   {
     *aValue = JSVAL_VOID;
     return true;
diff --git a/dom/bluetooth/gonk/BluetoothGonkService.h b/dom/bluetooth/gonk/BluetoothGonkService.h
index b9fff9c9a482..2895a6e2a5b1 100644
--- a/dom/bluetooth/gonk/BluetoothGonkService.h
+++ b/dom/bluetooth/gonk/BluetoothGonkService.h
@@ -18,6 +18,7 @@
 #ifndef mozilla_dom_bluetooth_bluetoothgonkservice_h__
 #define mozilla_dom_bluetooth_bluetoothgonkservice_h__
 
+#include "mozilla/Attributes.h"
 #include "BluetoothCommon.h"
 #include "BluetoothDBusService.h"
 
@@ -41,21 +42,21 @@ public:
    *
    * @return NS_OK if connection starts successfully, NS_ERROR_FAILURE otherwise
    */
-  virtual nsresult StartInternal();
+  virtual nsresult StartInternal() MOZ_OVERRIDE;
 
   /**
    * Stop the platform specific connection. Must be called from non-main thread.
    *
    * @return NS_OK if connection starts successfully, NS_ERROR_FAILURE otherwise
    */
-  virtual nsresult StopInternal();
+  virtual nsresult StopInternal() MOZ_OVERRIDE;
 
   /**
    * Get status of Bluetooth. Must be called from non-main thread.
    *
    * @return true if Bluetooth is enabled, false otherwise
    */
-  virtual bool IsEnabledInternal();
+  virtual bool IsEnabledInternal() MOZ_OVERRIDE;
 };
 
 END_BLUETOOTH_NAMESPACE
diff --git a/dom/bluetooth/linux/BluetoothDBusService.h b/dom/bluetooth/linux/BluetoothDBusService.h
index 7ba5e3ddd7e7..17c2f94739ab 100644
--- a/dom/bluetooth/linux/BluetoothDBusService.h
+++ b/dom/bluetooth/linux/BluetoothDBusService.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_bluetooth_bluetoothdbuseventservice_h__
 #define mozilla_dom_bluetooth_bluetoothdbuseventservice_h__
 
+#include "mozilla/Attributes.h"
 #include "BluetoothCommon.h"
 #include "mozilla/ipc/RawDBusConnection.h"
 #include "BluetoothService.h"
@@ -26,38 +27,38 @@ class BluetoothDBusService : public BluetoothService
 public:
   bool IsReady();
 
-  virtual nsresult StartInternal();
+  virtual nsresult StartInternal() MOZ_OVERRIDE;
 
-  virtual nsresult StopInternal();
+  virtual nsresult StopInternal() MOZ_OVERRIDE;
 
-  virtual bool IsEnabledInternal();
+  virtual bool IsEnabledInternal() MOZ_OVERRIDE;
 
   virtual nsresult GetDefaultAdapterPathInternal(
-                                             BluetoothReplyRunnable* aRunnable);
+                                             BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual nsresult GetConnectedDevicePropertiesInternal(uint16_t aProfileId,
-                                             BluetoothReplyRunnable* aRunnable);
+                                             BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual nsresult GetPairedDevicePropertiesInternal(
                                      const nsTArray<nsString>& aDeviceAddresses,
-                                     BluetoothReplyRunnable* aRunnable);
+                                     BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
-  virtual nsresult StartDiscoveryInternal(BluetoothReplyRunnable* aRunnable);
+  virtual nsresult StartDiscoveryInternal(BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
-  virtual nsresult StopDiscoveryInternal(BluetoothReplyRunnable* aRunnable);
+  virtual nsresult StopDiscoveryInternal(BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual nsresult
-  GetDevicePropertiesInternal(const BluetoothSignal& aSignal);
+  GetDevicePropertiesInternal(const BluetoothSignal& aSignal) MOZ_OVERRIDE;
 
   virtual nsresult
   SetProperty(BluetoothObjectType aType,
               const BluetoothNamedValue& aValue,
-              BluetoothReplyRunnable* aRunnable);
+              BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual bool
   GetDevicePath(const nsAString& aAdapterPath,
                 const nsAString& aDeviceAddress,
-                nsAString& aDevicePath);
+                nsAString& aDevicePath) MOZ_OVERRIDE;
 
   static bool
   AddServiceRecords(const char* serviceName,
@@ -82,44 +83,44 @@ public:
   GetScoSocket(const nsAString& aObjectPath,
                bool aAuth,
                bool aEncrypt,
-               mozilla::ipc::UnixSocketConsumer* aConsumer);
+               mozilla::ipc::UnixSocketConsumer* aConsumer) MOZ_OVERRIDE;
 
   virtual nsresult
   GetServiceChannel(const nsAString& aDeviceAddress,
                     const nsAString& aServiceUuid,
-                    BluetoothProfileManagerBase* aManager);
+                    BluetoothProfileManagerBase* aManager) MOZ_OVERRIDE;
 
   virtual bool
   UpdateSdpRecords(const nsAString& aDeviceAddress,
-                   BluetoothProfileManagerBase* aManager);
+                   BluetoothProfileManagerBase* aManager) MOZ_OVERRIDE;
 
   virtual nsresult
   CreatePairedDeviceInternal(const nsAString& aDeviceAddress,
                              int aTimeout,
-                             BluetoothReplyRunnable* aRunnable);
+                             BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual nsresult
   RemoveDeviceInternal(const nsAString& aDeviceObjectPath,
-                       BluetoothReplyRunnable* aRunnable);
+                       BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual bool
   SetPinCodeInternal(const nsAString& aDeviceAddress, const nsAString& aPinCode,
-                     BluetoothReplyRunnable* aRunnable);
+                     BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual bool
   SetPasskeyInternal(const nsAString& aDeviceAddress, uint32_t aPasskey,
-                     BluetoothReplyRunnable* aRunnable);
+                     BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual bool
   SetPairingConfirmationInternal(const nsAString& aDeviceAddress, bool aConfirm,
-                                 BluetoothReplyRunnable* aRunnable);
+                                 BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual bool
   SetAuthorizationInternal(const nsAString& aDeviceAddress, bool aAllow,
-                           BluetoothReplyRunnable* aRunnable);
+                           BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual nsresult
-  PrepareAdapterInternal();
+  PrepareAdapterInternal() MOZ_OVERRIDE;
 
   virtual void
   Connect(const nsAString& aDeviceAddress,
@@ -127,7 +128,7 @@ public:
           BluetoothReplyRunnable* aRunnable);
 
   virtual bool
-  IsConnected(uint16_t aProfileId);
+  IsConnected(uint16_t aProfileId) MOZ_OVERRIDE;
 
   virtual void
   Disconnect(const uint16_t aProfileId, BluetoothReplyRunnable* aRunnable);
@@ -136,24 +137,24 @@ public:
   SendFile(const nsAString& aDeviceAddress,
            BlobParent* aBlobParent,
            BlobChild* aBlobChild,
-           BluetoothReplyRunnable* aRunnable);
+           BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual void
   StopSendingFile(const nsAString& aDeviceAddress,
-                  BluetoothReplyRunnable* aRunnable);
+                  BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual void
   ConfirmReceivingFile(const nsAString& aDeviceAddress, bool aConfirm,
-                       BluetoothReplyRunnable* aRunnable);
+                       BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual void
-  ConnectSco(BluetoothReplyRunnable* aRunnable);
+  ConnectSco(BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual void
-  DisconnectSco(BluetoothReplyRunnable* aRunnable);
+  DisconnectSco(BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
   virtual void
-  IsScoConnected(BluetoothReplyRunnable* aRunnable);
+  IsScoConnected(BluetoothReplyRunnable* aRunnable) MOZ_OVERRIDE;
 
 private:
   nsresult SendGetPropertyMessage(const nsAString& aPath,
diff --git a/dom/camera/CameraControlImpl.h b/dom/camera/CameraControlImpl.h
index c79889b3bbe2..429e0219c99d 100644
--- a/dom/camera/CameraControlImpl.h
+++ b/dom/camera/CameraControlImpl.h
@@ -5,6 +5,7 @@
 #ifndef DOM_CAMERA_CAMERACONTROLIMPL_H
 #define DOM_CAMERA_CAMERACONTROLIMPL_H
 
+#include "mozilla/Attributes.h"
 #include "nsDOMFile.h"
 #include "nsProxyRelease.h"
 #include "DictionaryHelpers.h"
@@ -165,7 +166,7 @@ public:
     , mWindowId(aWindowId)
   { }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
 
@@ -202,7 +203,7 @@ public:
   }
 
   // Run() method is implementation specific.
-  NS_IMETHOD Run();
+  NS_IMETHOD Run() MOZ_OVERRIDE;
 
 protected:
   nsRefPtr<CameraControlImpl> mCameraControl;
@@ -231,7 +232,7 @@ public:
     DOM_CAMERA_LOGT("%s:%d : this=%p\n", __func__, __LINE__, this);
   }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     nsresult rv = mCameraControl->GetPreviewStreamImpl(this);
 
@@ -261,7 +262,7 @@ public:
 
   virtual ~AutoFocusResult() { }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
 
@@ -295,7 +296,7 @@ public:
     DOM_CAMERA_LOGT("%s:%d : this=%p\n", __func__, __LINE__, this);
   }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     DOM_CAMERA_LOGT("%s:%d\n", __func__, __LINE__);
     nsresult rv = mCameraControl->AutoFocusImpl(this);
@@ -334,7 +335,7 @@ public:
     DOM_CAMERA_LOGT("%s:%d : this=%p\n", __func__, __LINE__, this);
   }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
 
@@ -380,7 +381,7 @@ public:
     DOM_CAMERA_LOGT("%s:%d : this=%p\n", __func__, __LINE__, this);
   }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     DOM_CAMERA_LOGT("%s:%d\n", __func__, __LINE__);
     nsresult rv = mCameraControl->TakePictureImpl(this);
@@ -416,7 +417,7 @@ public:
 
   virtual ~StartRecordingResult() { }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
 
@@ -452,7 +453,7 @@ public:
     DOM_CAMERA_LOGT("%s:%d : this=%p\n", __func__, __LINE__, this);
   }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     DOM_CAMERA_LOGT("%s:%d\n", __func__, __LINE__);
     nsresult rv = mCameraControl->StartRecordingImpl(this);
@@ -496,7 +497,7 @@ public:
     DOM_CAMERA_LOGT("%s:%d : this=%p\n", __func__, __LINE__, this);
   }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     DOM_CAMERA_LOGT("%s:%d\n", __func__, __LINE__);
     nsresult rv = mCameraControl->StopRecordingImpl(this);
@@ -525,7 +526,7 @@ public:
     DOM_CAMERA_LOGT("%s:%d : this=%p\n", __func__, __LINE__, this);
   }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     DOM_CAMERA_LOGT("%s:%d\n", __func__, __LINE__);
     nsresult rv = mCameraControl->StartPreviewImpl(this);
@@ -554,7 +555,7 @@ public:
     DOM_CAMERA_LOGT("%s:%d : this=%p\n", __func__, __LINE__, this);
   }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     DOM_CAMERA_LOGT("%s:%d\n", __func__, __LINE__);
     mCameraControl->StopPreviewImpl(this);
@@ -577,7 +578,7 @@ public:
     , mOnErrorCb(new nsMainThreadPtrHolder<nsICameraErrorCallback>(onError))
   { }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     DOM_CAMERA_LOGI("%s:%d -- BEFORE IMPL\n", __func__, __LINE__);
     nsresult rv = mCameraControl->GetPreviewStreamVideoModeImpl(this);
@@ -613,7 +614,7 @@ public:
     DOM_CAMERA_LOGT("%s:%d : this=%p\n", __func__, __LINE__, this);
   }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
 
@@ -645,7 +646,7 @@ public:
     DOM_CAMERA_LOGT("%s:%d : this=%p\n", __func__, __LINE__, this);
   }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     DOM_CAMERA_LOGT("%s:%d\n", __func__, __LINE__);
     nsresult rv = mCameraControl->ReleaseHardwareImpl(this);
@@ -676,7 +677,7 @@ public:
     , mWindowId(aWindowId)
   { }
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     MOZ_ASSERT(NS_IsMainThread());
 
diff --git a/dom/camera/DOMCameraManager.h b/dom/camera/DOMCameraManager.h
index 4e44d9546fbb..bb4864340e85 100644
--- a/dom/camera/DOMCameraManager.h
+++ b/dom/camera/DOMCameraManager.h
@@ -81,7 +81,7 @@ public:
     , mCameraThread(aCameraThread)
   { }
 
-  NS_IMETHOD Run();
+  NS_IMETHOD Run() MOZ_OVERRIDE;
 
 protected:
   uint32_t mCameraId;
diff --git a/dom/devicestorage/DeviceStorageRequestParent.h b/dom/devicestorage/DeviceStorageRequestParent.h
index 4d23bf8e194f..e21b6e7c1f0e 100644
--- a/dom/devicestorage/DeviceStorageRequestParent.h
+++ b/dom/devicestorage/DeviceStorageRequestParent.h
@@ -6,6 +6,7 @@
 #ifndef mozilla_dom_devicestorage_DeviceStorageRequestParent_h
 #define mozilla_dom_devicestorage_DeviceStorageRequestParent_h
 
+#include "mozilla/Attributes.h"
 #include "mozilla/dom/devicestorage/PDeviceStorageRequestParent.h"
 #include "mozilla/dom/ContentChild.h"
 #include "mozilla/dom/ContentParent.h"
@@ -50,7 +51,7 @@ private:
     virtual ~CancelableRunnable() {
     }
 
-    NS_IMETHOD Run() {
+    NS_IMETHOD Run() MOZ_OVERRIDE {
       nsresult rv = NS_OK;
       if (!mCanceled) {
         rv = CancelableRun();
diff --git a/dom/devicestorage/nsDeviceStorage.h b/dom/devicestorage/nsDeviceStorage.h
index 8c74004069b3..8b101a1ee565 100644
--- a/dom/devicestorage/nsDeviceStorage.h
+++ b/dom/devicestorage/nsDeviceStorage.h
@@ -6,6 +6,7 @@
 #define nsDeviceStorage_h
 
 class nsPIDOMWindow;
+#include "mozilla/Attributes.h"
 #include "PCOMContentPermissionRequestChild.h"
 
 #include "DOMRequest.h"
@@ -72,7 +73,7 @@ public:
 
       ~InvalidateRunnable() {}
 
-      NS_IMETHOD Run()
+      NS_IMETHOD Run() MOZ_OVERRIDE
       {
         mozilla::RefPtr<DeviceStorageUsedSpaceCache::CacheEntry> cacheEntry;
         cacheEntry = mCache->GetCacheEntry(mStorageName);
@@ -169,7 +170,7 @@ public:
   ~ContinueCursorEvent();
   void Continue();
 
-  NS_IMETHOD Run();
+  NS_IMETHOD Run() MOZ_OVERRIDE;
 private:
   already_AddRefed<DeviceStorageFile> GetNextFile();
   nsRefPtr<mozilla::dom::DOMRequest> mRequest;
@@ -199,12 +200,12 @@ public:
   bool mOkToCallContinue;
   PRTime mSince;
 
-  virtual bool Recv__delete__(const bool& allow);
-  virtual void IPDLRelease();
+  virtual bool Recv__delete__(const bool& allow) MOZ_OVERRIDE;
+  virtual void IPDLRelease() MOZ_OVERRIDE;
 
   void GetStorageType(nsAString & aType);
 
-  void RequestComplete();
+  void RequestComplete() MOZ_OVERRIDE;
 
 private:
   ~nsDOMDeviceStorageCursor();
diff --git a/dom/file/ArchiveRequest.h b/dom/file/ArchiveRequest.h
index 9cec869aa8d4..00ac3e11cb2f 100644
--- a/dom/file/ArchiveRequest.h
+++ b/dom/file/ArchiveRequest.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_file_domarchiverequest_h__
 #define mozilla_dom_file_domarchiverequest_h__
 
+#include "mozilla/Attributes.h"
 #include "ArchiveReader.h"
 #include "DOMRequest.h"
 
@@ -40,7 +41,7 @@ public:
                  ArchiveReader* aReader);
 
   // nsIDOMEventTarget
-  virtual nsresult PreHandleEvent(nsEventChainPreVisitor& aVisitor);
+  virtual nsresult PreHandleEvent(nsEventChainPreVisitor& aVisitor) MOZ_OVERRIDE;
 
 public:
   // This is called by the DOMArchiveRequestEvent
diff --git a/dom/file/ArchiveZipEvent.h b/dom/file/ArchiveZipEvent.h
index 9525ae6f5187..67c39eaf4970 100644
--- a/dom/file/ArchiveZipEvent.h
+++ b/dom/file/ArchiveZipEvent.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_file_domarchivezipevent_h__
 #define mozilla_dom_file_domarchivezipevent_h__
 
+#include "mozilla/Attributes.h"
 #include "ArchiveEvent.h"
 
 #include "FileCommon.h"
@@ -27,10 +28,10 @@ public:
                  const nsAString& aEncoding);
   virtual ~ArchiveZipItem();
 
-  nsresult GetFilename(nsString& aFilename);
+  nsresult GetFilename(nsString& aFilename) MOZ_OVERRIDE;
 
   // From zipItem to DOMFile:
-  virtual nsIDOMFile* File(ArchiveReader* aArchiveReader);
+  virtual nsIDOMFile* File(ArchiveReader* aArchiveReader) MOZ_OVERRIDE;
 
 public: // for the event
   static uint32_t StrToInt32(const uint8_t* aStr);
@@ -57,7 +58,7 @@ public:
   ArchiveReaderZipEvent(ArchiveReader* aArchiveReader,
                         const nsAString& aEncoding);
 
-  nsresult Exec();
+  nsresult Exec() MOZ_OVERRIDE;
 
 private:
   nsString mEncoding;
diff --git a/dom/file/ArchiveZipFile.h b/dom/file/ArchiveZipFile.h
index 06a1ab888419..886ac685f3f1 100644
--- a/dom/file/ArchiveZipFile.h
+++ b/dom/file/ArchiveZipFile.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_file_domarchivefile_h__
 #define mozilla_dom_file_domarchivefile_h__
 
+#include "mozilla/Attributes.h"
 #include "nsDOMFile.h"
 
 #include "ArchiveReader.h"
@@ -57,7 +58,7 @@ public:
   }
 
   // Overrides:
-  NS_IMETHOD GetInternalStream(nsIInputStream**);
+  NS_IMETHOD GetInternalStream(nsIInputStream**) MOZ_OVERRIDE;
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ArchiveZipFile, nsDOMFileCC)
@@ -65,7 +66,7 @@ public:
 protected:
   virtual already_AddRefed<nsIDOMBlob> CreateSlice(uint64_t aStart,
                                                    uint64_t aLength,
-                                                   const nsAString& aContentType);
+                                                   const nsAString& aContentType) MOZ_OVERRIDE;
 
 private: // Data
   ZipCentral mCentral;
diff --git a/dom/file/DOMFileHandle.h b/dom/file/DOMFileHandle.h
index 310baa847049..0cbd58754b33 100644
--- a/dom/file/DOMFileHandle.h
+++ b/dom/file/DOMFileHandle.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_file_domfilehandle_h__
 #define mozilla_dom_file_domfilehandle_h__
 
+#include "mozilla/Attributes.h"
 #include "FileCommon.h"
 
 #include "FileHandle.h"
@@ -22,10 +23,10 @@ public:
          nsIFile* aFile);
 
   virtual already_AddRefed<nsISupports>
-  CreateStream(nsIFile* aFile, bool aReadOnly);
+  CreateStream(nsIFile* aFile, bool aReadOnly) MOZ_OVERRIDE;
 
   virtual already_AddRefed<nsIDOMFile>
-  CreateFileObject(LockedFile* aLockedFile, uint32_t aFileSize);
+  CreateFileObject(LockedFile* aLockedFile, uint32_t aFileSize) MOZ_OVERRIDE;
 
 protected:
   DOMFileHandle()
diff --git a/dom/file/File.h b/dom/file/File.h
index 29ea02d372f5..54725b2f8faa 100644
--- a/dom/file/File.h
+++ b/dom/file/File.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_file_file_h__
 #define mozilla_dom_file_file_h__
 
+#include "mozilla/Attributes.h"
 #include "FileCommon.h"
 
 #include "nsDOMFile.h"
@@ -48,10 +49,10 @@ public:
 
   // Overrides
   NS_IMETHOD
-  GetMozFullPathInternal(nsAString& aFullPath);
+  GetMozFullPathInternal(nsAString& aFullPath) MOZ_OVERRIDE;
 
   NS_IMETHOD
-  GetInternalStream(nsIInputStream** aStream);
+  GetInternalStream(nsIInputStream** aStream) MOZ_OVERRIDE;
 
 protected:
   // Create slice
@@ -63,22 +64,22 @@ protected:
 
   virtual already_AddRefed<nsIDOMBlob>
   CreateSlice(uint64_t aStart, uint64_t aLength,
-              const nsAString& aContentType);
+              const nsAString& aContentType) MOZ_OVERRIDE;
 
   virtual bool
-  IsStoredFile() const
+  IsStoredFile() const MOZ_OVERRIDE
   {
     return mStoredFile;
   }
 
   virtual bool
-  IsWholeFile() const
+  IsWholeFile() const MOZ_OVERRIDE
   {
     return mWholeFile;
   }
 
   virtual bool
-  IsSnapshot() const
+  IsSnapshot() const MOZ_OVERRIDE
   {
     return true;
   }
diff --git a/dom/file/FileRequest.h b/dom/file/FileRequest.h
index bea7dc7b628f..bf2727a56435 100644
--- a/dom/file/FileRequest.h
+++ b/dom/file/FileRequest.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_file_filerequest_h__
 #define mozilla_dom_file_filerequest_h__
 
+#include "mozilla/Attributes.h"
 #include "FileCommon.h"
 
 #include "DOMRequest.h"
@@ -27,7 +28,7 @@ public:
 
   // nsIDOMEventTarget
   virtual nsresult
-  PreHandleEvent(nsEventChainPreVisitor& aVisitor);
+  PreHandleEvent(nsEventChainPreVisitor& aVisitor) MOZ_OVERRIDE;
 
   void
   OnProgress(uint64_t aProgress, uint64_t aProgressMax)
diff --git a/dom/file/FileService.h b/dom/file/FileService.h
index 97f5933dc170..bfa4d92c00c4 100644
--- a/dom/file/FileService.h
+++ b/dom/file/FileService.h
@@ -70,16 +70,16 @@ private:
 
   public:
     NS_IMETHOD_(nsrefcnt)
-    AddRef();
+    AddRef() MOZ_OVERRIDE;
 
     NS_IMETHOD_(nsrefcnt)
-    Release();
+    Release() MOZ_OVERRIDE;
 
     inline nsresult
     Enqueue(FileHelper* aFileHelper);
 
     virtual void
-    OnFileHelperComplete(FileHelper* aFileHelper);
+    OnFileHelperComplete(FileHelper* aFileHelper) MOZ_OVERRIDE;
 
   private:
     inline
diff --git a/dom/file/LockedFile.h b/dom/file/LockedFile.h
index c5d4a0f3f637..d4e316e74df3 100644
--- a/dom/file/LockedFile.h
+++ b/dom/file/LockedFile.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_file_lockedfile_h__
 #define mozilla_dom_file_lockedfile_h__
 
+#include "mozilla/Attributes.h"
 #include "FileCommon.h"
 
 #include "nsIDOMLockedFile.h"
@@ -65,7 +66,7 @@ public:
 
   // nsIDOMEventTarget
   virtual nsresult
-  PreHandleEvent(nsEventChainPreVisitor& aVisitor);
+  PreHandleEvent(nsEventChainPreVisitor& aVisitor) MOZ_OVERRIDE;
 
   nsresult
   CreateParallelStream(nsISupports** aStream);
diff --git a/dom/file/MetadataHelper.h b/dom/file/MetadataHelper.h
index 3e9916780fb0..23e0d19ea6ef 100644
--- a/dom/file/MetadataHelper.h
+++ b/dom/file/MetadataHelper.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_file_metadatahelper_h__
 #define mozilla_dom_file_metadatahelper_h__
 
+#include "mozilla/Attributes.h"
 #include "FileCommon.h"
 
 #include "nsIFileStreams.h"
@@ -90,10 +91,10 @@ public:
   { }
 
   nsresult
-  DoAsyncRun(nsISupports* aStream);
+  DoAsyncRun(nsISupports* aStream) MOZ_OVERRIDE;
 
   nsresult
-  GetSuccessResult(JSContext* aCx, JS::Value* aVal);
+  GetSuccessResult(JSContext* aCx, JS::Value* aVal) MOZ_OVERRIDE;
 
 protected:
   class AsyncMetadataGetter : public AsyncHelper
@@ -107,7 +108,7 @@ protected:
 
   protected:
     nsresult
-    DoStreamWork(nsISupports* aStream);
+    DoStreamWork(nsISupports* aStream) MOZ_OVERRIDE;
 
   private:
     nsRefPtr<MetadataParameters> mParams;
diff --git a/dom/indexedDB/IDBDatabase.h b/dom/indexedDB/IDBDatabase.h
index af6a5e8ba0ce..7e1b722f7bd9 100644
--- a/dom/indexedDB/IDBDatabase.h
+++ b/dom/indexedDB/IDBDatabase.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_indexeddb_idbdatabase_h__
 #define mozilla_dom_indexeddb_idbdatabase_h__
 
+#include "mozilla/Attributes.h"
 #include "mozilla/dom/indexedDB/IndexedDatabase.h"
 
 #include "nsIDocument.h"
@@ -79,7 +80,7 @@ public:
   }
 
   // nsIDOMEventTarget
-  virtual nsresult PostHandleEvent(nsEventChainPostVisitor& aVisitor);
+  virtual nsresult PostHandleEvent(nsEventChainPostVisitor& aVisitor) MOZ_OVERRIDE;
 
   DatabaseInfo* Info() const
   {
diff --git a/dom/indexedDB/IDBRequest.h b/dom/indexedDB/IDBRequest.h
index be3d662fcf7f..259f486bf552 100644
--- a/dom/indexedDB/IDBRequest.h
+++ b/dom/indexedDB/IDBRequest.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_indexeddb_idbrequest_h__
 #define mozilla_dom_indexeddb_idbrequest_h__
 
+#include "mozilla/Attributes.h"
 #include "mozilla/dom/indexedDB/IndexedDatabase.h"
 
 #include "nsIIDBRequest.h"
@@ -41,7 +42,7 @@ public:
                                       JSContext* aCallingCx);
 
   // nsIDOMEventTarget
-  virtual nsresult PreHandleEvent(nsEventChainPreVisitor& aVisitor);
+  virtual nsresult PreHandleEvent(nsEventChainPreVisitor& aVisitor) MOZ_OVERRIDE;
 
   nsISupports* Source()
   {
@@ -139,7 +140,7 @@ public:
   void SetTransaction(IDBTransaction* aTransaction);
 
   // nsIDOMEventTarget
-  virtual nsresult PostHandleEvent(nsEventChainPostVisitor& aVisitor);
+  virtual nsresult PostHandleEvent(nsEventChainPostVisitor& aVisitor) MOZ_OVERRIDE;
 
   DOMError* GetError(ErrorResult& aRv)
   {
diff --git a/dom/indexedDB/IDBTransaction.h b/dom/indexedDB/IDBTransaction.h
index 68c88aacdd93..cacdf48705b2 100644
--- a/dom/indexedDB/IDBTransaction.h
+++ b/dom/indexedDB/IDBTransaction.h
@@ -7,6 +7,7 @@
 #ifndef mozilla_dom_indexeddb_idbtransaction_h__
 #define mozilla_dom_indexeddb_idbtransaction_h__
 
+#include "mozilla/Attributes.h"
 #include "mozilla/dom/indexedDB/IndexedDatabase.h"
 
 #include "mozIStorageConnection.h"
@@ -98,7 +99,7 @@ public:
   }
 
   // nsIDOMEventTarget
-  virtual nsresult PreHandleEvent(nsEventChainPreVisitor& aVisitor);
+  virtual nsresult PreHandleEvent(nsEventChainPreVisitor& aVisitor) MOZ_OVERRIDE;
 
   void OnNewRequest();
   void OnRequestFinished();
diff --git a/dom/indexedDB/ipc/IndexedDBParent.h b/dom/indexedDB/ipc/IndexedDBParent.h
index 79974c1118a4..1fe363b57c77 100644
--- a/dom/indexedDB/ipc/IndexedDBParent.h
+++ b/dom/indexedDB/ipc/IndexedDBParent.h
@@ -97,7 +97,7 @@ public:
   }
 
   NS_IMETHOD
-  HandleEvent(nsIDOMEvent* aEvent)
+  HandleEvent(nsIDOMEvent* aEvent) MOZ_OVERRIDE
   {
     return mActor ? mActor->HandleEvent(aEvent) : NS_OK;
   }
diff --git a/dom/ipc/ContentParent.h b/dom/ipc/ContentParent.h
index f2e65b0643af..f06571aa5c3b 100644
--- a/dom/ipc/ContentParent.h
+++ b/dom/ipc/ContentParent.h
@@ -111,10 +111,10 @@ public:
      * MessageManagerCallback methods that we override.
      */
     virtual bool DoSendAsyncMessage(const nsAString& aMessage,
-                                    const mozilla::dom::StructuredCloneData& aData);
-    virtual bool CheckPermission(const nsAString& aPermission);
-    virtual bool CheckManifestURL(const nsAString& aManifestURL);
-    virtual bool CheckAppHasPermission(const nsAString& aPermission);
+                                    const mozilla::dom::StructuredCloneData& aData) MOZ_OVERRIDE;
+    virtual bool CheckPermission(const nsAString& aPermission) MOZ_OVERRIDE;
+    virtual bool CheckManifestURL(const nsAString& aManifestURL) MOZ_OVERRIDE;
+    virtual bool CheckAppHasPermission(const nsAString& aPermission) MOZ_OVERRIDE;
 
     /** Notify that a tab is beginning its destruction sequence. */
     void NotifyTabDestroying(PBrowserParent* aTab);
@@ -167,7 +167,7 @@ public:
     void FriendlyName(nsAString& aName);
 
 protected:
-    void OnChannelConnected(int32_t pid);
+    void OnChannelConnected(int32_t pid) MOZ_OVERRIDE;
     virtual void ActorDestroy(ActorDestroyReason why);
 
 private:
diff --git a/dom/ipc/TabChild.h b/dom/ipc/TabChild.h
index 927fcd1f2f13..6f39cfa94e01 100644
--- a/dom/ipc/TabChild.h
+++ b/dom/ipc/TabChild.h
@@ -91,17 +91,17 @@ public:
       ? mMessageManager->SendSyncMessage(aMessageName, aObject, aCx, aArgc, aRetval)
       : NS_ERROR_NULL_POINTER;
   }
-  NS_IMETHOD GetContent(nsIDOMWindow** aContent);
-  NS_IMETHOD GetDocShell(nsIDocShell** aDocShell);
-  NS_IMETHOD Dump(const nsAString& aStr)
+  NS_IMETHOD GetContent(nsIDOMWindow** aContent) MOZ_OVERRIDE;
+  NS_IMETHOD GetDocShell(nsIDocShell** aDocShell) MOZ_OVERRIDE;
+  NS_IMETHOD Dump(const nsAString& aStr) MOZ_OVERRIDE
   {
     return mMessageManager ? mMessageManager->Dump(aStr) : NS_OK;
   }
-  NS_IMETHOD PrivateNoteIntentionalCrash();
+  NS_IMETHOD PrivateNoteIntentionalCrash() MOZ_OVERRIDE;
   NS_IMETHOD Btoa(const nsAString& aBinaryData,
-                  nsAString& aAsciiBase64String);
+                  nsAString& aAsciiBase64String) MOZ_OVERRIDE;
   NS_IMETHOD Atob(const nsAString& aAsciiString,
-                  nsAString& aBinaryData);
+                  nsAString& aBinaryData) MOZ_OVERRIDE;
 
   NS_IMETHOD AddEventListener(const nsAString& aType,
                               nsIDOMEventListener* aListener,
@@ -115,7 +115,7 @@ public:
   NS_IMETHOD AddEventListener(const nsAString& aType,
                               nsIDOMEventListener* aListener,
                               bool aUseCapture, bool aWantsUntrusted,
-                              uint8_t optional_argc)
+                              uint8_t optional_argc) MOZ_OVERRIDE
   {
     return nsDOMEventTargetHelper::AddEventListener(aType, aListener,
                                                     aUseCapture,
@@ -123,8 +123,8 @@ public:
                                                     optional_argc);
   }
 
-  virtual JSContext* GetJSContextForEventHandlers();
-  virtual nsIPrincipal* GetPrincipal();
+  virtual JSContext* GetJSContextForEventHandlers() MOZ_OVERRIDE;
+  virtual nsIPrincipal* GetPrincipal() MOZ_OVERRIDE;
 
   nsCOMPtr<nsIContentFrameMessageManager> mMessageManager;
   TabChild* mTabChild;
diff --git a/dom/media/MediaManager.h b/dom/media/MediaManager.h
index 7d0ef78f5409..b13d5114380f 100644
--- a/dom/media/MediaManager.h
+++ b/dom/media/MediaManager.h
@@ -212,7 +212,7 @@ class GetUserMediaNotificationEvent: public nsRunnable
     }
 
     NS_IMETHOD
-    Run()
+    Run() MOZ_OVERRIDE
     {
       NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
       // Make sure mStream is cleared and our reference to the DOMMediaStream
@@ -291,7 +291,7 @@ public:
   }
 
   NS_IMETHOD
-  Run()
+  Run() MOZ_OVERRIDE
   {
     SourceMediaStream *source = mListener->GetSourceStream();
     // No locking between these is required as all the callbacks for the
diff --git a/dom/plugins/base/nsPluginInstanceOwner.h b/dom/plugins/base/nsPluginInstanceOwner.h
index 1cf695ede46f..88b15e189717 100644
--- a/dom/plugins/base/nsPluginInstanceOwner.h
+++ b/dom/plugins/base/nsPluginInstanceOwner.h
@@ -7,6 +7,7 @@
 #ifndef nsPluginInstanceOwner_h_
 #define nsPluginInstanceOwner_h_
 
+#include "mozilla/Attributes.h"
 #include "npapi.h"
 #include "nsCOMPtr.h"
 #include "nsIPluginInstanceOwner.h"
@@ -60,19 +61,19 @@ public:
   
   NS_IMETHOD GetURL(const char *aURL, const char *aTarget,
                     nsIInputStream *aPostStream, 
-                    void *aHeadersData, uint32_t aHeadersDataLen);
+                    void *aHeadersData, uint32_t aHeadersDataLen) MOZ_OVERRIDE;
   
-  NS_IMETHOD ShowStatus(const PRUnichar *aStatusMsg);
+  NS_IMETHOD ShowStatus(const PRUnichar *aStatusMsg) MOZ_OVERRIDE;
   
-  NPError    ShowNativeContextMenu(NPMenu* menu, void* event);
+  NPError    ShowNativeContextMenu(NPMenu* menu, void* event) MOZ_OVERRIDE;
   
   NPBool     ConvertPoint(double sourceX, double sourceY, NPCoordinateSpace sourceSpace,
-                          double *destX, double *destY, NPCoordinateSpace destSpace);
+                          double *destX, double *destY, NPCoordinateSpace destSpace) MOZ_OVERRIDE;
   
   virtual NPError InitAsyncSurface(NPSize *size, NPImageFormat format,
-                                   void *initData, NPAsyncSurface *surface);
-  virtual NPError FinalizeAsyncSurface(NPAsyncSurface *surface);
-  virtual void SetCurrentAsyncSurface(NPAsyncSurface *surface, NPRect *changed);
+                                   void *initData, NPAsyncSurface *surface) MOZ_OVERRIDE;
+  virtual NPError FinalizeAsyncSurface(NPAsyncSurface *surface) MOZ_OVERRIDE;
+  virtual void SetCurrentAsyncSurface(NPAsyncSurface *surface, NPRect *changed) MOZ_OVERRIDE;
 
   //nsIPluginTagInfo interface
   NS_DECL_NSIPLUGINTAGINFO
diff --git a/dom/plugins/base/nsPluginTags.h b/dom/plugins/base/nsPluginTags.h
index 36d6682d6a81..1a8c618cb581 100644
--- a/dom/plugins/base/nsPluginTags.h
+++ b/dom/plugins/base/nsPluginTags.h
@@ -6,6 +6,7 @@
 #ifndef nsPluginTags_h_
 #define nsPluginTags_h_
 
+#include "mozilla/Attributes.h"
 #include "nscore.h"
 #include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
@@ -110,26 +111,26 @@ public:
   virtual ~DOMMimeTypeImpl() {
   }
 
-  NS_METHOD GetDescription(nsAString& aDescription)
+  NS_METHOD GetDescription(nsAString& aDescription) MOZ_OVERRIDE
   {
     aDescription.Assign(mDescription);
     return NS_OK;
   }
 
-  NS_METHOD GetEnabledPlugin(nsIDOMPlugin** aEnabledPlugin)
+  NS_METHOD GetEnabledPlugin(nsIDOMPlugin** aEnabledPlugin) MOZ_OVERRIDE
   {
     // this has to be implemented by the DOM version.
     *aEnabledPlugin = nullptr;
     return NS_OK;
   }
 
-  NS_METHOD GetSuffixes(nsAString& aSuffixes)
+  NS_METHOD GetSuffixes(nsAString& aSuffixes) MOZ_OVERRIDE
   {
     aSuffixes.Assign(mSuffixes);
     return NS_OK;
   }
 
-  NS_METHOD GetType(nsAString& aType)
+  NS_METHOD GetType(nsAString& aType) MOZ_OVERRIDE
   {
     aType.Assign(mType);
     return NS_OK;
diff --git a/dom/plugins/ipc/PluginProcessParent.h b/dom/plugins/ipc/PluginProcessParent.h
index 1b0aa6bc4c66..109eef9dbb9c 100644
--- a/dom/plugins/ipc/PluginProcessParent.h
+++ b/dom/plugins/ipc/PluginProcessParent.h
@@ -7,6 +7,7 @@
 #ifndef dom_plugins_PluginProcessParent_h
 #define dom_plugins_PluginProcessParent_h 1
 
+#include "mozilla/Attributes.h"
 #include "base/basictypes.h"
 
 #include "base/file_path.h"
@@ -35,7 +36,7 @@ public:
 
     void Delete();
 
-    virtual bool CanShutdown()
+    virtual bool CanShutdown() MOZ_OVERRIDE
     {
         return true;
     }
diff --git a/dom/src/events/nsJSEventListener.h b/dom/src/events/nsJSEventListener.h
index 73cd37624516..5570b6e81878 100644
--- a/dom/src/events/nsJSEventListener.h
+++ b/dom/src/events/nsJSEventListener.h
@@ -6,6 +6,7 @@
 #ifndef nsJSEventListener_h__
 #define nsJSEventListener_h__
 
+#include "mozilla/Attributes.h"
 #include "nsIDOMKeyEvent.h"
 #include "nsIJSEventListener.h"
 #include "nsIDOMEventListener.h"
@@ -32,7 +33,7 @@ public:
 
   // nsIJSEventListener
 
-  virtual size_t SizeOfIncludingThis(nsMallocSizeOfFun aMallocSizeOf) const
+  virtual size_t SizeOfIncludingThis(nsMallocSizeOfFun aMallocSizeOf) const MOZ_OVERRIDE
   {
     return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
   }
diff --git a/dom/src/geolocation/nsGeolocation.h b/dom/src/geolocation/nsGeolocation.h
index a795156d6e6f..0e0601b4f0b7 100644
--- a/dom/src/geolocation/nsGeolocation.h
+++ b/dom/src/geolocation/nsGeolocation.h
@@ -83,8 +83,8 @@ class nsGeolocationRequest
 
   ~nsGeolocationRequest();
 
-  bool Recv__delete__(const bool& allow);
-  void IPDLRelease() { Release(); }
+  virtual bool Recv__delete__(const bool& allow) MOZ_OVERRIDE;
+  virtual void IPDLRelease() MOZ_OVERRIDE { Release(); }
 
   int32_t WatchId() { return mWatchId; }
  private:
diff --git a/dom/src/jsurl/nsJSProtocolHandler.h b/dom/src/jsurl/nsJSProtocolHandler.h
index a6793476db30..69888a5b8da1 100644
--- a/dom/src/jsurl/nsJSProtocolHandler.h
+++ b/dom/src/jsurl/nsJSProtocolHandler.h
@@ -6,6 +6,7 @@
 #ifndef nsJSProtocolHandler_h___
 #define nsJSProtocolHandler_h___
 
+#include "mozilla/Attributes.h"
 #include "nsIProtocolHandler.h"
 #include "nsITextToSubURI.h"
 #include "nsIURI.h"
@@ -78,21 +79,21 @@ public:
     NS_DECL_ISUPPORTS_INHERITED
 
     // nsIURI overrides
-    virtual nsSimpleURI* StartClone(RefHandlingEnum refHandlingMode);
+    virtual nsSimpleURI* StartClone(RefHandlingEnum refHandlingMode) MOZ_OVERRIDE;
 
     // nsISerializable overrides
-    NS_IMETHOD Read(nsIObjectInputStream* aStream);
-    NS_IMETHOD Write(nsIObjectOutputStream* aStream);
+    NS_IMETHOD Read(nsIObjectInputStream* aStream) MOZ_OVERRIDE;
+    NS_IMETHOD Write(nsIObjectOutputStream* aStream) MOZ_OVERRIDE;
 
     // Override the nsIClassInfo method GetClassIDNoAlloc to make sure our
     // nsISerializable impl works right.
-    NS_IMETHOD GetClassIDNoAlloc(nsCID *aClassIDNoAlloc);
+    NS_IMETHOD GetClassIDNoAlloc(nsCID *aClassIDNoAlloc) MOZ_OVERRIDE;
     //NS_IMETHOD QueryInterface( const nsIID& aIID, void** aInstancePtr );
 
 protected:
     virtual nsresult EqualsInternal(nsIURI* other,
                                     RefHandlingEnum refHandlingMode,
-                                    bool* result);
+                                    bool* result) MOZ_OVERRIDE;
 private:
     nsCOMPtr<nsIURI> mBaseURI;
 };
diff --git a/dom/src/notification/DesktopNotification.h b/dom/src/notification/DesktopNotification.h
index 641be2d564b7..f22d6abf787e 100644
--- a/dom/src/notification/DesktopNotification.h
+++ b/dom/src/notification/DesktopNotification.h
@@ -156,7 +156,7 @@ class DesktopNotificationRequest : public nsIContentPermissionRequest,
   DesktopNotificationRequest(DesktopNotification* notification)
     : mDesktopNotification(notification) {}
 
-  NS_IMETHOD Run()
+  NS_IMETHOD Run() MOZ_OVERRIDE
   {
     nsCOMPtr<nsIContentPermissionPrompt> prompt =
       do_CreateInstance(NS_CONTENT_PERMISSION_PROMPT_CONTRACTID);
@@ -170,7 +170,7 @@ class DesktopNotificationRequest : public nsIContentPermissionRequest,
   {
   }
 
- bool Recv__delete__(const bool& allow)
+ virtual bool Recv__delete__(const bool& allow) MOZ_OVERRIDE
  {
    if (allow)
      (void) Allow();
@@ -178,7 +178,7 @@ class DesktopNotificationRequest : public nsIContentPermissionRequest,
      (void) Cancel();
    return true;
  }
- void IPDLRelease() { Release(); }
+ virtual void IPDLRelease() MOZ_OVERRIDE { Release(); }
 
   nsRefPtr<DesktopNotification> mDesktopNotification;
 };
diff --git a/dom/src/storage/DOMStorage.h b/dom/src/storage/DOMStorage.h
index af3645309d49..966466729345 100644
--- a/dom/src/storage/DOMStorage.h
+++ b/dom/src/storage/DOMStorage.h
@@ -6,6 +6,7 @@
 #ifndef nsDOMStorage_h___
 #define nsDOMStorage_h___
 
+#include "mozilla/Attributes.h"
 #include "nsIDOMStorage.h"
 #include "nsPIDOMStorage.h"
 #include "nsWeakReference.h"
@@ -25,15 +26,15 @@ class DOMStorage MOZ_FINAL : public nsIDOMStorage
   NS_DECL_NSIDOMSTORAGE
 
   // nsPIDOMStorage
-  virtual StorageType GetType() const;
-  virtual DOMStorageManager* GetManager() const { return mManager; }
-  virtual const DOMStorageCache* GetCache() const { return mCache; }
+  virtual StorageType GetType() const MOZ_OVERRIDE;
+  virtual DOMStorageManager* GetManager() const MOZ_OVERRIDE { return mManager; }
+  virtual const DOMStorageCache* GetCache() const MOZ_OVERRIDE { return mCache; }
 
-  virtual nsTArray<nsString>* GetKeys();
-  virtual nsIPrincipal* GetPrincipal();
-  virtual bool PrincipalEquals(nsIPrincipal* aPrincipal);
-  virtual bool CanAccess(nsIPrincipal* aPrincipal);
-  virtual bool IsPrivate() { return mIsPrivate; }
+  virtual nsTArray<nsString>* GetKeys() MOZ_OVERRIDE;
+  virtual nsIPrincipal* GetPrincipal() MOZ_OVERRIDE;
+  virtual bool PrincipalEquals(nsIPrincipal* aPrincipal) MOZ_OVERRIDE;
+  virtual bool CanAccess(nsIPrincipal* aPrincipal) MOZ_OVERRIDE;
+  virtual bool IsPrivate() MOZ_OVERRIDE { return mIsPrivate; }
 
   DOMStorage(DOMStorageManager* aManager,
              DOMStorageCache* aCache,
diff --git a/dom/workers/FileReaderSync.h b/dom/workers/FileReaderSync.h
index a07e0b2fc60c..23dfcd2f00a9 100644
--- a/dom/workers/FileReaderSync.h
+++ b/dom/workers/FileReaderSync.h
@@ -53,7 +53,7 @@ public:
                      ErrorResult& aRv);
 
   // From nsICharsetDetectionObserver
-  NS_IMETHOD Notify(const char *aCharset, nsDetectionConfident aConf);
+  NS_IMETHOD Notify(const char *aCharset, nsDetectionConfident aConf) MOZ_OVERRIDE;
 };
 
 END_WORKERS_NAMESPACE
diff --git a/dom/workers/WorkerPrivate.h b/dom/workers/WorkerPrivate.h
index 15074207f399..e94c9a46c7f8 100644
--- a/dom/workers/WorkerPrivate.h
+++ b/dom/workers/WorkerPrivate.h
@@ -6,6 +6,7 @@
 #ifndef mozilla_dom_workers_workerprivate_h__
 #define mozilla_dom_workers_workerprivate_h__
 
+#include "mozilla/Attributes.h"
 #include "Workers.h"
 
 #include "nsIContentSecurityPolicy.h"
@@ -133,7 +134,7 @@ protected:
   { }
 
   virtual bool
-  DispatchInternal();
+  DispatchInternal() MOZ_OVERRIDE;
 };
 
 class MainThreadSyncRunnable : public WorkerSyncRunnable
@@ -176,7 +177,7 @@ protected:
   { }
 
   virtual bool
-  DispatchInternal();
+  DispatchInternal() MOZ_OVERRIDE;
 };
 
 // SharedMutex is a small wrapper around an (internal) reference-counted Mutex