Match html canvas which is transferred to OffscreenCanvas to CSS style

cc/layers/surface_layer.h

Index: cc/layers/surface_layer.h
diff --git a/cc/layers/surface_layer.h b/cc/layers/surface_layer.h
index a66257d1bd94f6096dee8d9a9a614f70ad0777c8..9f2838bfc995c68c581184e987095642232f3a23 100644
--- a/cc/layers/surface_layer.h
+++ b/cc/layers/surface_layer.h
@@ -32,9 +32,11 @@ class CC_EXPORT SurfaceLayer : public Layer {
       const SatisfyCallback& satisfy_callback,
       const RequireCallback& require_callback);
 
+  // When stretch_content_to_fill_bounds is true, scale is unused.
   void SetSurfaceId(const SurfaceId& surface_id,
                     float scale,
-                    const gfx::Size& size);
+                    const gfx::Size& size,
+                    bool stretch_content_to_fill_bounds);
 
   // Layer overrides.
   std::unique_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl) override;
@@ -60,7 +62,8 @@ class CC_EXPORT SurfaceLayer : public Layer {
 
   SurfaceId surface_id_;
   gfx::Size surface_size_;
-  float surface_scale_;
+  float surface_scale_ = 1.f;
+  bool stretch_content_to_fill_bounds_ = false;
   SurfaceSequence destroy_sequence_;
   SatisfyCallback satisfy_callback_;
   RequireCallback require_callback_;