cc: RenderSurfaceImpl tile mask layer.

cc/layers/picture_layer.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/picture_layer.h"
 
 #include "base/auto_reset.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/picture_layer_impl.h"
@@ skipping 128 matching lines @@
   } else {
     // If this invalidation did not affect the recording source, then it can be
     // cleared as an optimization.
     last_updated_invalidation_.Clear();
   }
 
   return updated;
 }
 
 void PictureLayer::SetLayerMaskType(LayerMaskType mask_type) {
+  // We do not allow converting SINGLE_TEXTURE_MASK to MULTI_TEXTURE_MASK in
+  // order to avoid rerastering when a mask's transform is being animated.
+  if (mask_type_ == LayerMaskType::SINGLE_TEXTURE_MASK &&
+      LayerMaskType::MULTI_TEXTURE_MASK)
+    return;
   mask_type_ = mask_type;
 }
 
 sk_sp<SkPicture> PictureLayer::GetPicture() const {
   // We could either flatten the RecordingSource into a single SkPicture, or
   // paint a fresh one depending on what we intend to do with it.  For now we
   // just paint a fresh one to get consistent results.
   if (!DrawsContent())
     return nullptr;
 
@@ skipping 117 matching lines @@
     return false;
 
   return true;
 }
 
 const DisplayItemList* PictureLayer::GetDisplayItemList() {
   return picture_layer_inputs_.display_list.get();
 }
 
 }  // namespace cc