Bug 732091 - Part 3: Pass on the isFirstPaint flag from the PresShell to the compositor via the layer manager. r=tnikkel,bgirard

gfx/layers/Layers.h

@@ -486,6 +486,11 @@ public:
   LayerUserData* GetUserData(void* aKey)
   { return mUserData.Get(aKey); }
 
+  /**
+   * Flag the next paint as the first for a document.
+   */
+  virtual void SetIsFirstPaint() {}
+
   // We always declare the following logging symbols, because it's
   // extremely tricky to conditionally declare them.  However, for
   // ifndef MOZ_LAYERS_HAVE_LOG builds, they only have trivial

gfx/layers/basic/BasicLayers.cpp

@@ -3504,5 +3504,11 @@ BasicShadowLayerManager::IsCompositingCheap()
          LayerManager::IsCompositingCheap(GetParentBackendType());
 }
 
+void
+BasicShadowLayerManager::SetIsFirstPaint()
+{
+  ShadowLayerForwarder::SetIsFirstPaint();
+}
+
 }
 }

gfx/layers/basic/BasicLayers.h

@@ -267,6 +267,8 @@ public:
   virtual bool IsCompositingCheap();
   virtual bool HasShadowManagerInternal() const { return HasShadowManager(); }
 
+  virtual void SetIsFirstPaint() MOZ_OVERRIDE;
+
 private:
   /**
    * Forward transaction results to the parent context.

gfx/layers/ipc/CompositorParent.cpp

@@ -58,6 +58,7 @@ CompositorParent::CompositorParent(nsIWidget* aWidget)
   : mWidget(aWidget)
   , mCurrentCompositeTask(NULL)
   , mPaused(false)
+  , mIsFirstPaint(false)
 {
   MOZ_COUNT_CTOR(CompositorParent);
 }
@@ -315,8 +316,9 @@ CompositorParent::RequestViewTransform()
 #endif
 
 void
-CompositorParent::ShadowLayersUpdated()
+CompositorParent::ShadowLayersUpdated(bool isFirstPaint)
 {
+  mIsFirstPaint = mIsFirstPaint || isFirstPaint;
   const nsTArray<PLayersParent*>& shadowParents = ManagedPLayersParent();
   NS_ABORT_IF_FALSE(shadowParents.Length() <= 1,
                     "can only support at most 1 ShadowLayersParent");

gfx/layers/ipc/CompositorParent.h

@@ -91,7 +91,7 @@ public:
 
   virtual bool RecvStop() MOZ_OVERRIDE;
 
-  virtual void ShadowLayersUpdated() MOZ_OVERRIDE;
+  virtual void ShadowLayersUpdated(bool isFirstPaint) MOZ_OVERRIDE;
   void Destroy();
 
   LayerManager* GetLayerManager() { return mLayerManager; }
@@ -144,6 +144,13 @@ private:
   float mYScale;
   nsIntPoint mScrollOffset;
 
+  // When this flag is set, the next composition will be the first for a
+  // particular document (i.e. the document displayed on the screen will change).
+  // This happens when loading a new page or switching tabs. We notify the
+  // front-end (e.g. Java on Android) about this so that it take the new page
+  // size and zoom into account when providing us with the next view transform.
+  bool mIsFirstPaint;
+
   DISALLOW_EVIL_CONSTRUCTORS(CompositorParent);
 };
 

gfx/layers/ipc/ShadowLayers.cpp

@@ -128,6 +128,7 @@ struct AutoTxnEnd {
 ShadowLayerForwarder::ShadowLayerForwarder()
  : mShadowManager(NULL)
  , mParentBackend(LayerManager::LAYERS_NONE)
+ , mIsFirstPaint(false)
 {
   mTxn = new Transaction();
 }
@@ -325,11 +326,12 @@ ShadowLayerForwarder::EndTransaction(InfallibleTArray<EditReply>* aReplies)
 
   MOZ_LAYERS_LOG(("[LayersForwarder] sending transaction..."));
   RenderTraceScope rendertrace3("Foward Transaction", "000093");
-  if (!mShadowManager->SendUpdate(cset, false, aReplies)) {
+  if (!mShadowManager->SendUpdate(cset, mIsFirstPaint, aReplies)) {
     MOZ_LAYERS_LOG(("[LayersForwarder] WARNING: sending transaction failed!"));
     return false;
   }
 
+  mIsFirstPaint = false;
   MOZ_LAYERS_LOG(("[LayersForwarder] ... done"));
   return true;
 }

gfx/layers/ipc/ShadowLayers.h

@@ -308,6 +308,11 @@ public:
    */
   bool ShouldDoubleBuffer() { return GetParentBackendType() == LayerManager::LAYERS_BASIC; }
 
+  /**
+   * Flag the next paint as the first for a document.
+   */
+  void SetIsFirstPaint() { mIsFirstPaint = true; }
+
 protected:
   ShadowLayerForwarder();
 
@@ -332,6 +337,8 @@ private:
 
   Transaction* mTxn;
   LayersBackend mParentBackend;
+
+  bool mIsFirstPaint;
 };
 
 

gfx/layers/ipc/ShadowLayersManager.h

@@ -54,7 +54,7 @@ class ShadowLayersManager
 {
 
 public:
-  virtual void ShadowLayersUpdated() = 0;
+  virtual void ShadowLayersUpdated(bool isFirstPaint) = 0;
 };
 
 } // layers

gfx/layers/ipc/ShadowLayersParent.cpp

@@ -399,7 +399,7 @@ ShadowLayersParent::RecvUpdate(const InfallibleTArray<Edit>& cset,
   // other's buffer contents.
   ShadowLayerManager::PlatformSyncBeforeReplyUpdate();
 
-  mShadowLayersManager->ShadowLayersUpdated();
+  mShadowLayersManager->ShadowLayersUpdated(isFirstPaint);
 
 #ifdef COMPOSITOR_PERFORMANCE_WARNING
   printf_stderr("Compositor: Layers update took %i ms (blocking gecko).\n",

layout/base/nsPresShell.cpp

@@ -5370,6 +5370,11 @@ PresShell::Paint(nsIView*           aViewToPaint,
   LayerManager* layerManager =
     aWidgetToPaint->GetLayerManager(&isRetainingManager);
   NS_ASSERTION(layerManager, "Must be in paint event");
+
+  if (mIsFirstPaint) {
+    layerManager->SetIsFirstPaint();
+    mIsFirstPaint = false;
+  }
   layerManager->BeginTransaction();
 
   if (frame && isRetainingManager) {

layout/ipc/RenderFrameParent.cpp

@@ -516,7 +516,7 @@ RenderFrameParent::ContentViewScaleChanged(nsContentView* aView)
 }
 
 void
-RenderFrameParent::ShadowLayersUpdated()
+RenderFrameParent::ShadowLayersUpdated(bool isFirstPaint)
 {
   mFrameLoader->SetCurrentRemoteFrame(this);
 

layout/ipc/RenderFrameParent.h

@@ -86,7 +86,7 @@ public:
 
   void ContentViewScaleChanged(nsContentView* aView);
 
-  virtual void ShadowLayersUpdated() MOZ_OVERRIDE;
+  virtual void ShadowLayersUpdated(bool isFirstPaint) MOZ_OVERRIDE;
 
   NS_IMETHOD BuildDisplayList(nsDisplayListBuilder* aBuilder,
                               nsSubDocumentFrame* aFrame,