Implements core logic for Pixel Canvas

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index 9d6e5882fbfd81c8c51b68dc5b4b16c9b07c9cd5..42aae947ac530f09094e2b2992160a8a95286ab8 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -1045,6 +1045,12 @@ void LayerTreeHost::SetDeviceScaleFactor(float device_scale_factor) {
   SetNeedsCommit();
 }
 
+void LayerTreeHost::SetRecordingScaleFactor(float recording_scale_factor) {
+  if (recording_scale_factor_ == recording_scale_factor)
+    return;
+  recording_scale_factor_ = recording_scale_factor;
+}
+
 void LayerTreeHost::SetPaintedDeviceScaleFactor(
     float painted_device_scale_factor) {
   if (painted_device_scale_factor_ == painted_device_scale_factor)