Clean up cc/paint interfaces

cc/paint/paint_surface.h

 // Copyright 2017 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_PAINT_PAINT_SURFACE_H_
 #define CC_PAINT_PAINT_SURFACE_H_
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/optional.h"
@@ skipping 21 matching lines @@
   static sk_sp<PaintSurface> MakeRasterN32Premul(
       int width,
       int height,
       const SkSurfaceProps* props = nullptr) {
     sk_sp<SkSurface> s = SkSurface::MakeRasterN32Premul(width, height, props);
     return sk_make_sp<PaintSurface>(std::move(s));
   }
 
   int width() const { return surface_->width(); }
   int height() const { return surface_->height(); }
-  uint32_t generationID() { return surface_->generationID(); }
 
   PaintCanvas* getCanvas() {
     if (!canvas_.has_value())
       canvas_.emplace(surface_->getCanvas());
     return &canvas_.value();
   }
 
  private:
   const sk_sp<SkSurface> surface_;
   base::Optional<SkiaPaintCanvas> canvas_;
 
   DISALLOW_COPY_AND_ASSIGN(PaintSurface);
 };
 
 }  // namespace cc
 
 #endif  // CC_PAINT_PAINT_SURFACE_H_