Use LatencyInfoSwapPromise to track LatencyInfo through compositor

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 ac471c395aea52fc303b0de0fa3d523e89421248..b5c368b72dfdcbf15e642caa849a2cc604d4792d 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -382,8 +382,6 @@ void LayerTreeHost::FinishCommitOnImplThread(LayerTreeHostImpl* host_impl) {
                                          min_page_scale_factor_,
                                          max_page_scale_factor_);
   sync_tree->SetPageScaleDelta(page_scale_delta / sent_page_scale_delta);
-  sync_tree->SetLatencyInfo(latency_info_);
-  latency_info_.Clear();
 
   sync_tree->PassSwapPromises(&swap_promise_list_);
 
@@ -705,10 +703,6 @@ void LayerTreeHost::SetVisible(bool visible) {
   proxy_->SetVisible(visible);
 }
 
-void LayerTreeHost::SetLatencyInfo(const ui::LatencyInfo& latency_info) {
-  latency_info_.MergeWith(latency_info);
-}
-
 void LayerTreeHost::StartPageScaleAnimation(gfx::Vector2d target_offset,
                                             bool use_anchor,
                                             float scale,
@@ -1271,9 +1265,6 @@ bool LayerTreeHost::ScheduleMicroBenchmark(
 }
 
 void LayerTreeHost::QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise) {
-  if (proxy_->HasImplThread()) {
-    DCHECK(proxy_->CommitRequested() || proxy_->BeginMainFrameRequested());
-  }
   DCHECK(swap_promise);
   if (swap_promise_list_.size() > kMaxQueuedSwapPromiseNumber)
     BreakSwapPromises(SwapPromise::SWAP_PROMISE_LIST_OVERFLOW);