Update from chromium https://crrev.com/304586

cc/resources/raster_source.h

 // Copyright 2014 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_RESOURCES_RASTER_SOURCE_H_
 #define CC_RESOURCES_RASTER_SOURCE_H_
 
 #include <vector>
 
 #include "base/memory/ref_counted.h"
@@ skipping 63 matching lines @@
   virtual bool CoversRect(const gfx::Rect& content_rect,
                           float contents_scale) const = 0;
 
   // Returns true if this raster source has anything to rasterize.
   virtual bool HasRecordings() const = 0;
 
   // Informs the raster source that it should attempt to use distance field text
   // during rasterization.
   virtual void SetShouldAttemptToUseDistanceFieldText() = 0;
 
+  virtual void SetBackgoundColor(SkColor background_color) = 0;
+  virtual void SetRequiresClear(bool requires_clear) = 0;
+
   // Return true iff this raster source would benefit from using distance
   // field text.
   virtual bool ShouldAttemptToUseDistanceFieldText() const = 0;
 
   // Tracing functionality.
   virtual void DidBeginTracing() = 0;
   virtual void AsValueInto(base::debug::TracedValue* array) const = 0;
   virtual skia::RefPtr<SkPicture> GetFlattenedPicture() = 0;
 
-  // TODO(vmpstr): This should be a layer property.
-  virtual bool IsMask() const = 0;
-
  protected:
   friend class base::RefCountedThreadSafe<RasterSource>;
 
   RasterSource() {}
   virtual ~RasterSource() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(RasterSource);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_RASTER_SOURCE_H_