paint: Introduce PaintImage that wraps SkImage in paint calls.

cc/paint/skia_paint_canvas.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_SKIA_PAINT_CANVAS_H_
 #define CC_PAINT_SKIA_PAINT_CANVAS_H_
 
 #include <memory>
 
 #include "base/compiler_specific.h"
@@ skipping 79 matching lines @@
   void drawArc(const SkRect& oval,
                SkScalar start_angle,
                SkScalar sweep_angle,
                bool use_center,
                const PaintFlags& flags) override;
   void drawRoundRect(const SkRect& rect,
                      SkScalar rx,
                      SkScalar ry,
                      const PaintFlags& flags) override;
   void drawPath(const SkPath& path, const PaintFlags& flags) override;
-  void drawImage(sk_sp<const SkImage> image,
+  void drawImage(const PaintImage& image,
                  SkScalar left,
                  SkScalar top,
                  const PaintFlags* flags) override;
-  void drawImageRect(sk_sp<const SkImage> image,
+  void drawImageRect(const PaintImage& image,
                      const SkRect& src,
                      const SkRect& dst,
                      const PaintFlags* flags,
                      SrcRectConstraint constraint) override;
   void drawBitmap(const SkBitmap& bitmap,
                   SkScalar left,
                   SkScalar top,
                   const PaintFlags* flags) override;
 
   void drawText(const void* text,
@@ skipping 41 matching lines @@
  private:
   SkCanvas* canvas_;
   std::unique_ptr<SkCanvas> owned_;
 
   DISALLOW_COPY_AND_ASSIGN(SkiaPaintCanvas);
 };
 
 }  // namespace cc
 
 #endif  // CC_PAINT_SKIA_PAINT_CANVAS_H_