added virtual destructors where necessary as pointed out by bruce@cybersight.com.

gfx/src/nsImageGroup.cpp

@@ -42,7 +42,7 @@ class ImageGroupImpl : public nsIImageGroup
 {
 public:
   ImageGroupImpl(nsIImageManager *aManager);
-  ~ImageGroupImpl();
+  virtual ~ImageGroupImpl();
 
   nsresult Init(nsIDeviceContext *aDeviceContext, nsIURLGroup* aURLGroup);
 

gfx/src/nsImageNetContextAsync.cpp

@@ -49,7 +49,7 @@ public:
                       nsIURLGroup* aURLGroup,
                       nsReconnectCB aReconnectCallback,
                       void* aReconnectArg);
-  ~ImageNetContextImpl();
+  virtual ~ImageNetContextImpl();
 
   NS_DECL_ISUPPORTS
 
@@ -104,7 +104,7 @@ public:
   static void KeepPumpingStream(nsITimer *aTimer, void *aClosure);
 
 protected:
-  ~ImageConsumer();
+  virtual ~ImageConsumer();
   ilIURL *mURL;
   PRBool mInterrupted;
   ImageNetContextImpl *mContext;

gfx/src/nsImageNetContextSync.cpp

@@ -37,7 +37,7 @@ static NS_DEFINE_IID(kNetServiceCID, NS_NETSERVICE_CID);
 class ImageNetContextSyncImpl : public ilINetContext {
 public:
   ImageNetContextSyncImpl(NET_ReloadMethod aReloadPolicy);
-  ~ImageNetContextSyncImpl();
+  virtual ~ImageNetContextSyncImpl();
 
   NS_DECL_ISUPPORTS
 

gfx/src/nsImageRequest.h

@@ -31,7 +31,7 @@ class ilINetContext;
 class ImageRequestImpl : public nsIImageRequest {
 public:
   ImageRequestImpl();
-  ~ImageRequestImpl();
+  virtual ~ImageRequestImpl();
   
   nsresult Init(IL_GroupContext *aGroupContext, const char* aUrl, 
                 nsIImageRequestObserver *aObserver,

gfx/src/nsImageSystemServices.cpp

@@ -29,7 +29,7 @@ public:
   static ImageSystemServicesImpl *sSS;
 
   ImageSystemServicesImpl();
-  ~ImageSystemServicesImpl();
+  virtual ~ImageSystemServicesImpl();
 
   NS_DECL_AND_IMPL_ZEROING_OPERATOR_NEW
 

gfx/src/nsImageURL.cpp

@@ -33,7 +33,7 @@ static NS_DEFINE_IID(kIImageURLIID, IL_IURL_IID);
 class ImageURLImpl : public ilIURL {
 public:
   ImageURLImpl(void);
-  ~ImageURLImpl();
+  virtual ~ImageURLImpl();
 
   NS_DECL_ISUPPORTS