cc: Add a helper function for transforming rects between surface spaces

cc/trees/layer_tree_host_common_unittest.cc

Index: cc/trees/layer_tree_host_common_unittest.cc
diff --git a/cc/trees/layer_tree_host_common_unittest.cc b/cc/trees/layer_tree_host_common_unittest.cc
index 45782b01bf6d9403e695142a57a70c7010b534cf..4f4511d9efd59b2dd51ce33977b0d5d559cf3a9b 100644
--- a/cc/trees/layer_tree_host_common_unittest.cc
+++ b/cc/trees/layer_tree_host_common_unittest.cc
@@ -4038,9 +4038,14 @@ TEST_F(LayerTreeHostCommonTest, ClipRectOfSurfaceWhoseParentIsAClipChild) {
   clip_parent->SetMasksToBounds(true);
   render_surface1->SetMasksToBounds(true);
 
-  ExecuteCalculateDrawProperties(root);
+  float device_scale_factor = 1.f;
+  ExecuteCalculateDrawProperties(root, device_scale_factor);
   EXPECT_EQ(gfx::Rect(50, 50),
             render_surface2->GetRenderSurface()->clip_rect());
+  device_scale_factor = 2.f;
+  ExecuteCalculateDrawProperties(root, device_scale_factor);
+  EXPECT_EQ(gfx::Rect(100, 100),
+            render_surface2->GetRenderSurface()->clip_rect());
 }
 
 TEST_F(LayerTreeHostCommonTest, RenderSurfaceContentRectWhenLayerNotDrawn) {