Use LatencyInfoSwapPromise to track LatencyInfo through compositor

cc/trees/layer_tree_impl.cc

Index: cc/trees/layer_tree_impl.cc
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index ea3218d536450a5bdf8847322613798ad681af68..eb1d471c499f6dc637aa67a7b814f7016e3253f1 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -120,9 +120,6 @@ void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
     next_activation_forces_redraw_ = false;
   }
 
-  target_tree->SetLatencyInfo(latency_info_);
-  latency_info_.Clear();
-
   target_tree->PassSwapPromises(&swap_promise_list_);
 
   target_tree->SetPageScaleFactorAndLimits(
@@ -464,8 +461,6 @@ void LayerTreeImpl::PushPersistedState(LayerTreeImpl* pending_tree) {
   pending_tree->SetCurrentlyScrollingLayer(
       LayerTreeHostCommon::FindLayerInSubtree(pending_tree->root_layer(),
           currently_scrolling_layer_ ? currently_scrolling_layer_->id() : 0));
-  pending_tree->SetLatencyInfo(latency_info_);
-  latency_info_.Clear();
 }
 
 static void DidBecomeActiveRecursive(LayerImpl* layer) {
@@ -699,18 +694,6 @@ void LayerTreeImpl::UpdateRootScrollLayerSizeDelta() {
       scrollable_viewport_size - original_viewport_size);
 }
 
-void LayerTreeImpl::SetLatencyInfo(const ui::LatencyInfo& latency_info) {
-  latency_info_.MergeWith(latency_info);
-}
-
-const ui::LatencyInfo& LayerTreeImpl::GetLatencyInfo() {
-  return latency_info_;
-}
-
-void LayerTreeImpl::ClearLatencyInfo() {
-  latency_info_.Clear();
-}
-
 void LayerTreeImpl::QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise) {
   DCHECK(swap_promise);
   if (swap_promise_list_.size() > kMaxQueuedSwapPromiseNumber)
@@ -725,9 +708,9 @@ void LayerTreeImpl::PassSwapPromises(
   new_swap_promise->clear();
 }
 
-void LayerTreeImpl::FinishSwapPromises() {
+void LayerTreeImpl::FinishSwapPromises(CompositorFrameMetadata* metadata) {
   for (size_t i = 0; i < swap_promise_list_.size(); i++)
-    swap_promise_list_[i]->DidSwap();
+    swap_promise_list_[i]->DidSwap(metadata);
   swap_promise_list_.clear();
 }