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 e204d8f1ab408a83ce2f318a683a2d611bbdf728..7f6b7200415c079e4fd636254a91770c4e0d98cd 100644
--- a/cc/paint/display_item_list.h
+++ b/cc/paint/display_item_list.h
@@ -138,6 +138,9 @@ 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);
@@ -178,6 +181,11 @@ class CC_PAINT_EXPORT DisplayItemList
 
   size_t op_count_ = 0u;
 
+  // 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.
+  bool pixel_canvas_enabled_ = false;
+
   friend class base::RefCountedThreadSafe<DisplayItemList>;
   FRIEND_TEST_ALL_PREFIXES(DisplayItemListTest, BytesUsed);
   DISALLOW_COPY_AND_ASSIGN(DisplayItemList);