Bug 618533 - forward oom notifications to child content process. r=jdm a=blocking-fennec

dom/ipc/ContentChild.cpp

@@ -586,5 +586,15 @@ ContentChild::RecvScreenSizeChanged(const gfxIntSize& size)
   return true;
 }
 
+bool
+ContentChild::RecvFlushMemory(const nsString& reason)
+{
+    nsCOMPtr<nsIObserverService> os =
+        mozilla::services::GetObserverService();
+    if (os)
+	os->NotifyObservers(nsnull, "memory-pressure", reason.get());
+  return true;
+}
+
 } // namespace dom
 } // namespace mozilla

dom/ipc/ContentChild.h

@@ -131,6 +131,9 @@ public:
                                          const double& z);
 
     virtual bool RecvScreenSizeChanged(const gfxIntSize &size);
+
+    virtual bool RecvFlushMemory(const nsString& reason);
+
 #ifdef ANDROID
     gfxIntSize GetScreenSize() { return mScreenSize; }
 #endif

dom/ipc/ContentParent.cpp

@@ -116,7 +116,9 @@ ContentParent::GetSingleton(PRBool aForceNew)
                     }
                 }
                 obs->AddObserver(
-                  parent, NS_IPC_IOSERVICE_SET_OFFLINE_TOPIC, PR_FALSE); 
+                  parent, NS_IPC_IOSERVICE_SET_OFFLINE_TOPIC, PR_FALSE);
+
+                obs->AddObserver(parent, "memory-pressure", PR_FALSE); 
             }
             nsCOMPtr<nsIThreadInternal>
                 threadInt(do_QueryInterface(NS_GetCurrentThread()));
@@ -354,8 +356,12 @@ ContentParent::Observe(nsISupports* aSubject,
     if (!mIsAlive || !mSubprocess)
         return NS_OK;
 
+    // listening for memory pressure event
+    if (!strcmp(aTopic, "memory-pressure")) {
+        SendFlushMemory(nsDependentString(aData));
+    }
     // listening for remotePrefs...
-    if (!strcmp(aTopic, "nsPref:changed")) {
+    else if (!strcmp(aTopic, "nsPref:changed")) {
         // We know prefs are ASCII here.
         NS_LossyConvertUTF16toASCII strData(aData);
 

dom/ipc/PContent.ipdl

@@ -116,6 +116,8 @@ child:
 
     ScreenSizeChanged(gfxIntSize size);
 
+    FlushMemory(nsString reason);
+
 parent:
     PNecko();
     PCrashReporter();