Bug 1301301, part 3 - Implement Begin and EndCycleCollectionCallback in CCJSContext. r=smaug

This will let my later patch run code at the start and end of each CC.

This patch should not change any behavior.

MozReview-Commit-ID: Fu6v3wo8qKB

dom/workers/RuntimeService.cpp

@@ -1099,16 +1099,6 @@ public:
   {
   }
 
-  virtual void
-  BeginCycleCollectionCallback() override
-  {
-  }
-
-  virtual void
-  EndCycleCollectionCallback(CycleCollectorResults &aResults) override
-  {
-  }
-
   void
   DispatchDeferredDeletion(bool aContinuation, bool aPurge) override
   {

js/xpconnect/src/XPCJSContext.cpp

@@ -665,6 +665,7 @@ XPCJSContext::PrepareForForgetSkippable()
 void
 XPCJSContext::BeginCycleCollectionCallback()
 {
+    CycleCollectedJSContext::BeginCycleCollectionCallback();
     nsJSContext::BeginCycleCollectionCallback();
 
     nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
@@ -676,6 +677,7 @@ XPCJSContext::BeginCycleCollectionCallback()
 void
 XPCJSContext::EndCycleCollectionCallback(CycleCollectorResults& aResults)
 {
+    CycleCollectedJSContext::EndCycleCollectionCallback(aResults);
     nsJSContext::EndCycleCollectionCallback(aResults);
 
     nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();

xpcom/base/CycleCollectedJSContext.cpp

@@ -1330,6 +1330,16 @@ CycleCollectedJSContext::DumpJSHeap(FILE* aFile)
   js::DumpHeap(Context(), aFile, js::CollectNurseryBeforeDump);
 }
 
+void
+CycleCollectedJSContext::BeginCycleCollectionCallback()
+{
+}
+
+void
+CycleCollectedJSContext::EndCycleCollectionCallback(CycleCollectorResults& aResults)
+{
+}
+
 void
 CycleCollectedJSContext::ProcessStableStateQueue()
 {

xpcom/base/CycleCollectedJSContext.h

@@ -321,8 +321,8 @@ public:
   void DumpJSHeap(FILE* aFile);
 
   virtual void PrepareForForgetSkippable() = 0;
-  virtual void BeginCycleCollectionCallback() = 0;
+  virtual void BeginCycleCollectionCallback();
-  virtual void EndCycleCollectionCallback(CycleCollectorResults& aResults) = 0;
+  virtual void EndCycleCollectionCallback(CycleCollectorResults& aResults);
   virtual void DispatchDeferredDeletion(bool aContinuation, bool aPurge = false) = 0;
 
   JSContext* Context() const