Bug 610727 - Mark canvas layers inactive when relevant. r=roc a=blocking-fennec

content/canvas/src/WebGLContext.cpp

@@ -622,6 +622,7 @@ WebGLContext::GetCanvasLayer(CanvasLayer *aOldLayer,
         if (mInvalidated) {
             aOldLayer->Updated(nsIntRect(0, 0, mWidth, mHeight));
             mInvalidated = PR_FALSE;
+            HTMLCanvasElement()->GetPrimaryCanvasFrame()->MarkLayersActive();
         }
         return aOldLayer;
     }

content/canvas/src/nsCanvasRenderingContext2D.cpp

@@ -4066,6 +4066,7 @@ nsCanvasRenderingContext2D::GetCanvasLayer(CanvasLayer *aOldLayer,
             // of the rectangle based on Redraw args.
             aOldLayer->Updated(nsIntRect(0, 0, mWidth, mHeight));
             MarkContextClean();
+            HTMLCanvasElement()->GetPrimaryCanvasFrame()->MarkLayersActive();
         }
 
         return aOldLayer;

gfx/layers/Layers.h

@@ -1,4 +1,4 @@
-/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  * ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
@@ -474,6 +474,11 @@ public:
   static bool IsLogEnabled();
   static PRLogModuleInfo* GetLog() { return sLog; }
 
+  PRBool IsCompositingCheap(LayerManager::LayersBackend aBackend)
+  { return LAYERS_BASIC != aBackend; }
+
+  virtual PRBool IsCompositingCheap() { return PR_TRUE; }
+
 protected:
   nsRefPtr<Layer> mRoot;
   LayerUserDataSet mUserData;

gfx/layers/basic/BasicLayers.cpp

@@ -1,4 +1,4 @@
-/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  * ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
@@ -2778,6 +2778,14 @@ BasicShadowLayerManager::Hold(Layer* aLayer)
   mKeepAlive.AppendElement(aLayer);
   return shadowable;
 }
+
+PRBool
+BasicShadowLayerManager::IsCompositingCheap()
+{
+  // Whether compositing is cheap depends on the parent backend.
+  return mShadowManager &&
+         LayerManager::IsCompositingCheap(GetParentBackendType());
+}
 #endif  // MOZ_IPC
 
 }

gfx/layers/basic/BasicLayers.h

@@ -1,4 +1,4 @@
-/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  * ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
@@ -184,6 +184,8 @@ public:
 
   void SetTransactionIncomplete() { mTransactionIncomplete = true; }
 
+  virtual PRBool IsCompositingCheap() { return PR_FALSE; }
+
 protected:
 #ifdef DEBUG
   enum TransactionPhase {
@@ -269,6 +271,8 @@ public:
     mShadowManager = aShadowManager;
   }
 
+  virtual PRBool IsCompositingCheap();
+
 private:
   /**
    * Forward transaction results to the parent context.

layout/generic/nsHTMLCanvasFrame.cpp

@@ -105,9 +105,11 @@ public:
   virtual LayerState GetLayerState(nsDisplayListBuilder* aBuilder,
                                    LayerManager* aManager)
   {
-    // XXX we should have some kind of activity timeout here so that
-    // inactive canvases can be composited into the background
-    return mozilla::LAYER_ACTIVE;
+    // If compositing is cheap, just do that
+    if (aManager->IsCompositingCheap())
+      return mozilla::LAYER_ACTIVE;
+
+    return mFrame->AreLayersMarkedActive() ? LAYER_ACTIVE : LAYER_INACTIVE;
   }
 };
 
@@ -120,6 +122,21 @@ NS_NewHTMLCanvasFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 
 NS_IMPL_FRAMEARENA_HELPERS(nsHTMLCanvasFrame)
 
+NS_IMETHODIMP
+nsHTMLCanvasFrame::Init(nsIContent* aContent,
+                        nsIFrame*   aParent,
+                        nsIFrame*   aPrevInFlow)
+{
+  nsresult rv = nsSplittableFrame::Init(aContent, aParent, aPrevInFlow);
+
+  // We can fill in the canvas before the canvas frame is created, in
+  // which case we never get around to marking the layer active. Therefore,
+  // we mark it active here when we create the frame.
+  MarkLayersActive();
+
+  return rv;
+}
+
 nsHTMLCanvasFrame::~nsHTMLCanvasFrame()
 {
 }

layout/generic/nsHTMLCanvasFrame.h

@@ -62,6 +62,10 @@ public:
 
   nsHTMLCanvasFrame(nsStyleContext* aContext) : nsSplittableFrame(aContext) {}
 
+  NS_IMETHOD Init(nsIContent* aContent,
+                  nsIFrame*   aParent,
+                  nsIFrame*   aPrevInFlow);
+
   NS_IMETHOD BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                               const nsRect&           aDirtyRect,
                               const nsDisplayListSet& aLists);