Bug 627661 - RGBA surface clear was broken in 593733 r=roc,mattwoodrow a=approval2.0

gfx/layers/opengl/ThebesLayerOGL.cpp

@@ -595,6 +595,12 @@ BasicBufferOGL::BeginPaint(ContentType aContentType)
     result.mContext = new gfxContext(surf);
   } else {
     result.mContext = new gfxContext(mTexImage->BeginUpdate(result.mRegionToDraw));
+    if (mTexImage->GetContentType() == gfxASurface::CONTENT_COLOR_ALPHA) {
+      gfxUtils::ClipToRegion(result.mContext, result.mRegionToDraw);
+      result.mContext->SetOperator(gfxContext::OPERATOR_CLEAR);
+      result.mContext->Fill();
+      result.mContext->SetOperator(gfxContext::OPERATOR_OVER);
+    }
   }
   if (!result.mContext) {
     NS_WARNING("unable to get context for update");

gfx/thebes/GLContext.cpp

@@ -589,13 +589,6 @@ BasicTextureImage::BeginUpdate(nsIntRegion& aRegion)
 
     mUpdateSurface->SetDeviceOffset(gfxPoint(-rgnSize.x, -rgnSize.y));
 
-    if (format == gfxASurface::ImageFormatARGB32) {
-      // Clear the returned surface because it might have been re-used.
-      nsRefPtr<gfxContext> ctx = new gfxContext(mUpdateSurface);
-      ctx->SetOperator(gfxContext::OPERATOR_CLEAR);
-      ctx->Paint();
-    }
-
     return mUpdateSurface;
 }