cc: Use multiple PrepareTiles approaches

cc/trees/thread_proxy.cc

Index: cc/trees/thread_proxy.cc
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index 3010fba95c32165329df0ad5ea7a3d56d8c2a879..5a7e6a16442a3516bf9db261c8d46661de0f0c54 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -395,6 +395,10 @@ void ThreadProxy::NotifyReadyToDraw() {
   impl().scheduler->NotifyReadyToDraw();
 }
 
+void ThreadProxy::SetRequiresHighResToDraw(bool required) {
+  impl().scheduler->SetRequiresHighResToDraw(required);
+}
+
 void ThreadProxy::SetNeedsCommitOnImplThread() {
   TRACE_EVENT0("cc", "ThreadProxy::SetNeedsCommitOnImplThread");
   DCHECK(IsImplThread());
@@ -511,9 +515,9 @@ void ThreadProxy::SetNeedsAnimateOnImplThread() {
   impl().scheduler->SetNeedsAnimate();
 }
 
-void ThreadProxy::SetNeedsPrepareTilesOnImplThread() {
+void ThreadProxy::SetNeedsPrepareTilesOnImplThread(bool for_commit) {
   DCHECK(IsImplThread());
-  impl().scheduler->SetNeedsPrepareTiles();
+  impl().scheduler->SetNeedsPrepareTiles(for_commit);
 }
 
 void ThreadProxy::SetNeedsRedrawRectOnImplThread(const gfx::Rect& damage_rect) {
@@ -1349,7 +1353,7 @@ void ThreadProxy::RenewTreePriority() {
     // Once we enter NEW_CONTENTS_TAKES_PRIORITY mode, visible tiles on active
     // tree might be freed. We need to set RequiresHighResToDraw to ensure that
     // high res tiles will be required to activate pending tree.
-    impl().layer_tree_host_impl->SetRequiresHighResToDraw();
+    impl().layer_tree_host_impl->SetRequiresHighResToDraw(true);
     priority = NEW_CONTENT_TAKES_PRIORITY;
   }
 
@@ -1396,11 +1400,6 @@ void ThreadProxy::DidActivateSyncTree() {
       impl().last_begin_main_frame_args;
 }
 
-void ThreadProxy::DidPrepareTiles() {
-  DCHECK(IsImplThread());
-  impl().scheduler->DidPrepareTiles();
-}
-
 void ThreadProxy::DidCompletePageScaleAnimationOnImplThread() {
   DCHECK(IsImplThread());
   Proxy::MainThreadTaskRunner()->PostTask(