cc: Distinguish single texture mask from normal masks

cc/layers/layer.h

 // Copyright 2010 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.
 
 #ifndef CC_LAYERS_LAYER_H_
 #define CC_LAYERS_LAYER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 294 matching lines @@
   // This is only virtual for tests.
   // TODO(awoloszyn): Remove this once we no longer need it for tests
   virtual bool DrawsContent() const;
 
   // This methods typically need to be overwritten by derived classes.
   // TODO(chrishtr): Blink no longer resizes anything during paint. We can
   // remove this.
   virtual void SavePaintProperties();
   // Returns true iff anything was updated that needs to be committed.
   virtual bool Update();
   virtual void SetIsMask(bool is_mask) {}

[enne (OOO), 2017/02/09 18:37:06]

Sorry for the API nit, but because these two functions are related and some
combinations don't make sense, like IsSingleTextureMask(true) and IsMask(false),
but can you make this SetMaskType with an enum of NO_MASK, SINGLE_TEXTURE_MASK,
... MASK? (not sure what to call the normal type).

+  virtual void SetIsSingleTextureMask(bool is_single_texture_mask_) {}
   virtual bool IsSuitableForGpuRasterization() const;
 
   virtual std::unique_ptr<base::trace_event::ConvertableToTraceFormat>
   TakeDebugInfo();
   virtual void didUpdateMainThreadScrollingReasons();
 
   void SetLayerClient(LayerClient* client) { inputs_.client = client; }
 
   virtual bool IsSnapped();
 
@@ skipping 331 matching lines @@
   // These all act like draw properties, so don't need push properties.
   gfx::Rect visible_layer_rect_;
   size_t num_unclipped_descendants_;
 
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_H_