Bug 991513 - Part 3: Combine BeginPaint/PrepareFrame and EndPaint/OnTransaction. r=nrc

gfx/layers/client/ClientThebesLayer.cpp

@@ -38,8 +38,6 @@ ClientThebesLayer::PaintThebes()
   NS_ASSERTION(ClientManager()->InDrawing(),
                "Can only draw in drawing phase");
   
-  mContentClient->PrepareFrame();
-
   uint32_t flags = RotatedContentBuffer::PAINT_CAN_DRAW_ROTATED;
 #ifndef MOZ_WIDGET_ANDROID
   if (ClientManager()->CompositorMightResample()) {
@@ -124,18 +122,6 @@ ClientThebesLayer::RenderLayer()
   mContentClient->BeginPaint();
   PaintThebes();
   mContentClient->EndPaint();
-  // It is very important that this is called after EndPaint, because destroying
-  // textures is a three stage process:
-  // 1. We are done with the buffer and move it to ContentClient::mOldTextures,
-  // that happens in DestroyBuffers which is may be called indirectly from
-  // PaintThebes.
-  // 2. The content client calls RemoveTextureClient on the texture clients in
-  // mOldTextures and forgets them. They then become invalid. The compositable
-  // client keeps a record of IDs. This happens in EndPaint.
-  // 3. An IPC message is sent to destroy the corresponding texture host. That
-  // happens from OnTransaction.
-  // It is important that these steps happen in order.
-  mContentClient->OnTransaction();
 }
 
 already_AddRefed<ThebesLayer>

gfx/layers/client/ContentClient.cpp

@@ -89,6 +89,23 @@ ContentClient::CreateContentClient(CompositableForwarder* aForwarder)
   return new ContentClientSingleBuffered(aForwarder);
 }
 
+void
+ContentClient::EndPaint()
+{
+  // It is very important that this is called after any overridden EndPaint behaviour,
+  // because destroying textures is a three stage process:
+  // 1. We are done with the buffer and move it to ContentClient::mOldTextures,
+  // that happens in DestroyBuffers which is may be called indirectly from
+  // PaintThebes.
+  // 2. The content client calls RemoveTextureClient on the texture clients in
+  // mOldTextures and forgets them. They then become invalid. The compositable
+  // client keeps a record of IDs. This happens in EndPaint.
+  // 3. An IPC message is sent to destroy the corresponding texture host. That
+  // happens from OnTransaction.
+  // It is important that these steps happen in order.
+  OnTransaction();
+}
+
 // We pass a null pointer for the ContentClient Forwarder argument, which means
 // this client will not have a ContentHost on the other side.
 ContentClientBasic::ContentClientBasic()
@@ -162,6 +179,7 @@ ContentClientRemoteBuffer::EndPaint()
   if (mTextureClientOnWhite && mTextureClientOnWhite->IsLocked()) {
     mTextureClientOnWhite->Unlock();
   }
+  ContentClientRemote::EndPaint();
 }
 
 bool
@@ -378,8 +396,10 @@ ContentClientDoubleBuffered::SwapBuffers(const nsIntRegion& aFrontUpdatedRegion)
 }
 
 void
-ContentClientDoubleBuffered::PrepareFrame()
+ContentClientDoubleBuffered::BeginPaint()
 {
+  ContentClientRemoteBuffer::BeginPaint();
+
   mIsNewBuffer = false;
 
   if (!mFrontAndBackBufferDiffer) {

gfx/layers/client/ContentClient.h

@@ -63,7 +63,6 @@ class ThebesLayer;
  * it alive anymore, so we clear mOldTextures.
  *
  * The sequence for painting is: call BeginPaint on the content client;
- * call PrepareFrame on the content client;
  * call BeginPaintBuffer on the content client. That will initialise the buffer
  * for painting, by calling RotatedContentBuffer::BeginPaint (usually) which
  * will call back to ContentClient::FinalizeFrame to finalize update of the
@@ -71,7 +70,6 @@ class ThebesLayer;
  * BorrowDrawTargetForPainting to get a DrawTarget to paint into. Then paint.
  * Then return that DrawTarget using ReturnDrawTarget.
  * Call EndPaint on the content client;
- * call OnTransaction on the content client.
  *
  * SwapBuffers is called in response to the transaction reply from the compositor.
  */
@@ -99,8 +97,6 @@ public:
                                                        RotatedContentBuffer::DrawIterator* aIter = nullptr) = 0;
   virtual void ReturnDrawTargetToBuffer(gfx::DrawTarget*& aReturned) = 0;
 
-  virtual void PrepareFrame() {}
-
   // Called as part of the layers transation reply. Conveys data about our
   // buffer(s) from the compositor. If appropriate we should swap references
   // to our buffers.
@@ -108,8 +104,7 @@ public:
 
   // call before and after painting into this content client
   virtual void BeginPaint() {}
-  virtual void EndPaint() {}
-
+  virtual void EndPaint();
 };
 
 /**
@@ -333,7 +328,7 @@ public:
 
   virtual void SwapBuffers(const nsIntRegion& aFrontUpdatedRegion) MOZ_OVERRIDE;
 
-  virtual void PrepareFrame() MOZ_OVERRIDE;
+  virtual void BeginPaint() MOZ_OVERRIDE;
 
   virtual void FinalizeFrame(const nsIntRegion& aRegionToDraw) MOZ_OVERRIDE;
 
@@ -439,6 +434,7 @@ public:
     if (IsSurfaceDescriptorValid(mUpdateDescriptorOnWhite)) {
       mForwarder->DestroySharedSurface(&mUpdateDescriptorOnWhite);
     }
+    ContentClientRemote::EndPaint();
   }
 
 private: