Rename paint data structures

cc/playback/discardable_image_map.h

Index: cc/playback/discardable_image_map.h
diff --git a/cc/playback/discardable_image_map.h b/cc/playback/discardable_image_map.h
index b521fff04ce503c6949a0cbc17343f7d69c5a68d..c910519df131d64e61236ab78f2a4f8d780e866a 100644
--- a/cc/playback/discardable_image_map.h
+++ b/cc/playback/discardable_image_map.h
@@ -10,8 +10,8 @@
 
 #include "cc/base/cc_export.h"
 #include "cc/base/rtree.h"
+#include "cc/paint/paint_canvas.h"
 #include "cc/playback/draw_image.h"
-#include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
@@ -32,11 +32,11 @@ class CC_EXPORT DiscardableImageMap {
                             const gfx::Size& bounds);
     ~ScopedMetadataGenerator();
 
-    SkCanvas* canvas() { return metadata_canvas_.get(); }
+    PaintCanvas* canvas() { return metadata_canvas_.get(); }
 
    private:
     DiscardableImageMap* image_map_;
-    std::unique_ptr<SkCanvas> metadata_canvas_;
+    std::unique_ptr<PaintCanvas> metadata_canvas_;
   };
 
   DiscardableImageMap();
@@ -51,7 +51,7 @@ class CC_EXPORT DiscardableImageMap {
   friend class ScopedMetadataGenerator;
   friend class DiscardableImageMapTest;
 
-  std::unique_ptr<SkCanvas> BeginGeneratingMetadata(const gfx::Size& bounds);
+  std::unique_ptr<PaintCanvas> BeginGeneratingMetadata(const gfx::Size& bounds);
   void EndGeneratingMetadata();
 
   std::vector<std::pair<DrawImage, gfx::Rect>> all_images_;