Implements core logic for Pixel Canvas

cc/paint/display_item_list.h

Index: cc/paint/display_item_list.h
diff --git a/cc/paint/display_item_list.h b/cc/paint/display_item_list.h
index f74456e62909461de5aab8bccb6d424113f1f072..0152da578611af7c66d7d2b831882b66c829acde 100644
--- a/cc/paint/display_item_list.h
+++ b/cc/paint/display_item_list.h
@@ -129,6 +129,9 @@ class CC_PAINT_EXPORT DisplayItemList
   // an empty state.
   sk_sp<PaintRecord> ReleaseAsRecord();
 
+  bool pixel_canvas_enabled() const { return pixel_canvas_enabled_; }
+  void set_pixel_canvas_enabled(bool value) { pixel_canvas_enabled_ = value; }
+
  private:
   FRIEND_TEST_ALL_PREFIXES(DisplayItemListTest, AsValueWithNoOps);
   FRIEND_TEST_ALL_PREFIXES(DisplayItemListTest, AsValueWithOps);
@@ -175,6 +178,12 @@ class CC_PAINT_EXPORT DisplayItemList
   // Finalize().
   bool retain_visual_rects_ = false;
 
+  // Set true if we are using pixel canvas. This mode allows us to records all
+  // canvas draw commands in pixel aligned measurements and scale elements using
+  // the corner points. Use compositor switch --enable-pixel-canvas-recording to
+  // enable this mode.
+  bool pixel_canvas_enabled_ = false;
+
   friend class base::RefCountedThreadSafe<DisplayItemList>;
   FRIEND_TEST_ALL_PREFIXES(DisplayItemListTest, BytesUsed);
   DISALLOW_COPY_AND_ASSIGN(DisplayItemList);