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 3ab29fa0e247b276d8b259eccf1e82c1185b4e84..953004e7e8ed000383be5bdbd79b200b11b007b9 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -1085,6 +1085,12 @@ 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)