Bug 822898 - Implement pointer events. Detect Pointer Listeners. r=smaug

content/base/src/nsNodeUtils.cpp

@@ -503,6 +503,9 @@ nsNodeUtils::CloneAndAdopt(nsINode *aNode, bool aClone, bool aDeep,
           if (elm->MayHaveMouseEnterLeaveEventListener()) {
             window->SetHasMouseEnterLeaveEventListeners();
           }
+          if (elm->MayHavePointerEnterLeaveEventListener()) {
+            window->SetHasPointerEnterLeaveEventListeners();
+          }
         }
       }
     }

dom/base/nsGlobalWindow.cpp

@@ -555,6 +555,7 @@ nsPIDOMWindow::nsPIDOMWindow(nsPIDOMWindow *aOuterWindow)
   mIsHandlingResizeEvent(false), mIsInnerWindow(aOuterWindow != nullptr),
   mMayHavePaintEventListener(false), mMayHaveTouchEventListener(false),
   mMayHaveMouseEnterLeaveEventListener(false),
+  mMayHavePointerEnterLeaveEventListener(false),
   mIsModalContentWindow(false),
   mIsActive(false), mIsBackground(false),
   mInnerWindow(nullptr), mOuterWindow(aOuterWindow),

dom/base/nsPIDOMWindow.h

@@ -483,6 +483,25 @@ public:
     mMayHaveMouseEnterLeaveEventListener = true;
   }
 
+  /**
+   * Call this to check whether some node (this window, its document,
+   * or content in that document) has a Pointerenter/leave event listener.
+   */
+  bool HasPointerEnterLeaveEventListeners()
+  {
+    return mMayHavePointerEnterLeaveEventListener;
+  }
+
+  /**
+   * Call this to indicate that some node (this window, its document,
+   * or content in that document) has a Pointerenter/leave event listener.
+   */
+  void SetHasPointerEnterLeaveEventListeners()
+  {
+    mMayHavePointerEnterLeaveEventListener = true;
+  }
+
+
   virtual JSObject* GetCachedXBLPrototypeHandler(nsXBLPrototypeHandler* aKey) = 0;
   virtual void CacheXBLPrototypeHandler(nsXBLPrototypeHandler* aKey,
                                         JS::Handle<JSObject*> aHandler) = 0;
@@ -733,6 +752,7 @@ protected:
   bool                   mMayHavePaintEventListener;
   bool                   mMayHaveTouchEventListener;
   bool                   mMayHaveMouseEnterLeaveEventListener;
+  bool                   mMayHavePointerEnterLeaveEventListener;
 
   // This variable is used on both inner and outer windows (and they
   // should match).

dom/events/nsEventListenerManager.cpp

@@ -94,6 +94,7 @@ nsEventListenerManager::nsEventListenerManager(EventTarget* aTarget) :
   mMayHaveAudioAvailableEventListener(false),
   mMayHaveTouchEventListener(false),
   mMayHaveMouseEnterLeaveEventListener(false),
+  mMayHavePointerEnterLeaveEventListener(false),
   mClearingListeners(false),
   mIsMainThreadELM(NS_IsMainThread()),
   mNoListenerForEvent(0),
@@ -340,6 +341,21 @@ nsEventListenerManager::AddEventListenerInternal(
     if (window && !aFlags.mInSystemGroup) {
       window->SetHasTouchEventListeners();
     }
+  } else if (aType >= NS_POINTER_EVENT_START && aType <= NS_POINTER_LOST_CAPTURE) {
+    nsPIDOMWindow* window = GetInnerWindowForTarget();
+    if (aTypeAtom == nsGkAtoms::onpointerenter ||
+        aTypeAtom == nsGkAtoms::onpointerleave) {
+      mMayHavePointerEnterLeaveEventListener = true;
+      if (window) {
+#ifdef DEBUG
+        nsCOMPtr<nsIDocument> d = window->GetExtantDoc();
+        NS_WARN_IF_FALSE(!nsContentUtils::IsChromeDoc(d),
+                         "Please do not use pointerenter/leave events in chrome. "
+                         "They are slower than pointerover/out!");
+#endif
+        window->SetHasPointerEnterLeaveEventListeners();
+      }
+    }
   } else if (aTypeAtom == nsGkAtoms::onmouseenter ||
              aTypeAtom == nsGkAtoms::onmouseleave) {
     mMayHaveMouseEnterLeaveEventListener = true;

dom/events/nsEventListenerManager.h

@@ -399,6 +399,7 @@ public:
   bool MayHaveTouchEventListener() { return mMayHaveTouchEventListener; }
 
   bool MayHaveMouseEnterLeaveEventListener() { return mMayHaveMouseEnterLeaveEventListener; }
+  bool MayHavePointerEnterLeaveEventListener() { return mMayHavePointerEnterLeaveEventListener; }
 
   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 
@@ -548,9 +549,10 @@ protected:
   uint32_t mMayHaveAudioAvailableEventListener : 1;
   uint32_t mMayHaveTouchEventListener : 1;
   uint32_t mMayHaveMouseEnterLeaveEventListener : 1;
+  uint32_t mMayHavePointerEnterLeaveEventListener : 1;
   uint32_t mClearingListeners : 1;
   uint32_t mIsMainThreadELM : 1;
-  uint32_t mNoListenerForEvent : 23;
+  uint32_t mNoListenerForEvent : 22;
 
   nsAutoTObserverArray<nsListenerStruct, 2> mListeners;
   mozilla::dom::EventTarget*                mTarget;  //WEAK