Bug 951554. Change the high level painting functions. r=nical

--HG--
extra : rebase_source : bcbed6d9d4e46d4b21854954789fe6ba28cdf3cc

gfx/layers/basic/BasicThebesLayer.cpp

@@ -169,11 +169,6 @@ BasicThebesLayer::Validate(LayerManager::DrawThebesLayerCallback aCallback,
     return;
   }
 
-  bool canUseOpaqueSurface = CanUseOpaqueSurface();
-  ContentType contentType =
-    canUseOpaqueSurface ? GFX_CONTENT_COLOR :
-                          GFX_CONTENT_COLOR_ALPHA;
-
   uint32_t flags = 0;
 #ifndef MOZ_WIDGET_ANDROID
   if (BasicManager()->CompositorMightResample()) {
@@ -189,31 +184,30 @@ BasicThebesLayer::Validate(LayerManager::DrawThebesLayerCallback aCallback,
     flags |= RotatedContentBuffer::PAINT_NO_ROTATION;
   }
   PaintState state =
-    mContentClient->BeginPaintBuffer(this, contentType, flags);
+    mContentClient->BeginPaintBuffer(this, flags);
   mValidRegion.Sub(mValidRegion, state.mRegionToInvalidate);
 
-  if (state.mTarget) {
+  if (DrawTarget* target = mContentClient->BorrowDrawTargetForPainting(this, state)) {
     // The area that became invalid and is visible needs to be repainted
     // (this could be the whole visible area if our buffer switched
     // from RGB to RGBA, because we might need to repaint with
     // subpixel AA)
     state.mRegionToInvalidate.And(state.mRegionToInvalidate,
                                   GetEffectiveVisibleRegion());
-    nsIntRegion extendedDrawRegion = state.mRegionToDraw;
-    SetAntialiasingFlags(this, state.mTarget);
+    SetAntialiasingFlags(this, target);
 
     RenderTraceInvalidateStart(this, "FFFF00", state.mRegionToDraw.GetBounds());
 
-    nsRefPtr<gfxContext> ctx = gfxContext::ContextForDrawTarget(state.mTarget);
+    nsRefPtr<gfxContext> ctx = gfxContext::ContextForDrawTarget(target);
     PaintBuffer(ctx,
-                state.mRegionToDraw, extendedDrawRegion, state.mRegionToInvalidate,
+                state.mRegionToDraw, state.mRegionToDraw, state.mRegionToInvalidate,
                 state.mDidSelfCopy,
                 state.mClip,
                 aCallback, aCallbackData);
     MOZ_LAYERS_LOG_IF_SHADOWABLE(this, ("Layer::Mutated(%p) PaintThebes", this));
     Mutated();
     ctx = nullptr;
-    mContentClient->ReturnDrawTarget(state.mTarget);
+    mContentClient->ReturnDrawTarget(target);
 
     RenderTraceInvalidateEnd(this, "FFFF00");
   } else {

gfx/layers/client/ClientThebesLayer.cpp

@@ -36,17 +36,9 @@ ClientThebesLayer::PaintThebes()
   NS_ASSERTION(ClientManager()->InDrawing(),
                "Can only draw in drawing phase");
   
-  //TODO: This is going to copy back pixels that we might end up
-  // drawing over anyway. It would be nice if we could avoid
-  // this duplication.
-  mContentClient->SyncFrontBufferToBackBuffer();
-
-  bool canUseOpaqueSurface = CanUseOpaqueSurface();
-  ContentType contentType =
-    canUseOpaqueSurface ? GFX_CONTENT_COLOR :
-                          GFX_CONTENT_COLOR_ALPHA;
-
   {
+    mContentClient->PrepareFrame();
+
     uint32_t flags = 0;
 #ifndef MOZ_WIDGET_ANDROID
     if (ClientManager()->CompositorMightResample()) {
@@ -59,27 +51,26 @@ ClientThebesLayer::PaintThebes()
     }
 #endif
     PaintState state =
-      mContentClient->BeginPaintBuffer(this, contentType, flags);
+      mContentClient->BeginPaintBuffer(this, flags);
     mValidRegion.Sub(mValidRegion, state.mRegionToInvalidate);
 
-    if (state.mTarget) {
+    if (DrawTarget* target = mContentClient->BorrowDrawTargetForPainting(this, state)) {
       // The area that became invalid and is visible needs to be repainted
       // (this could be the whole visible area if our buffer switched
       // from RGB to RGBA, because we might need to repaint with
       // subpixel AA)
       state.mRegionToInvalidate.And(state.mRegionToInvalidate,
                                     GetEffectiveVisibleRegion());
-      nsIntRegion extendedDrawRegion = state.mRegionToDraw;
-      SetAntialiasingFlags(this, state.mTarget);
+      SetAntialiasingFlags(this, target);
 
-      nsRefPtr<gfxContext> ctx = gfxContext::ContextForDrawTarget(state.mTarget);
+      nsRefPtr<gfxContext> ctx = gfxContext::ContextForDrawTarget(target);
       PaintBuffer(ctx,
-                  state.mRegionToDraw, extendedDrawRegion, state.mRegionToInvalidate,
+                  state.mRegionToDraw, state.mRegionToDraw, state.mRegionToInvalidate,
                   state.mDidSelfCopy, state.mClip);
       MOZ_LAYERS_LOG_IF_SHADOWABLE(this, ("Layer::Mutated(%p) PaintThebes", this));
       Mutated();
       ctx = nullptr;
-      mContentClient->ReturnDrawTarget(state.mTarget);
+      mContentClient->ReturnDrawTarget(target);
     } else {
       // It's possible that state.mRegionToInvalidate is nonempty here,
       // if we are shrinking the valid region to nothing. So use mRegionToDraw