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 9565c57a4d259e37350e903de9a3cd8b78b015e5..ef4bcbfd2c182f31936b00d580625bee727b0bc3 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) {
@@ -699,16 +694,18 @@ 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();
+// TODO(miletus): The merge here is a temporary hack. Should change the
+// function to be
+// TakeLatencyInfo(std::vector<ui::LatencyInfo>* latency_info)
+// Once we remove the LatencyInfo merge in the gpu side.
+void LayerTreeImpl::TakeLatencyInfo(ui::LatencyInfo* latency_info) {

[danakj, 2013/11/26 19:17:53]

Why isn't this going through the DidSwap() method? We shouldn't be using the
CompositorFrame for plumbing this info at all anymore should we?

[Yufeng Shen (Slow to review), 2013/11/27 20:05:33]

Removed.

Changed the DidSwap() signature to be
virtual void DidSwap(CompositorFrameMetadata* metadata)

so that LatencyInfoSwapPromise::DidSwap(CompositorFrameMetadata* metadata)
will merge its latencyinfo into metadata.

+  ScopedPtrVector<SwapPromise>::iterator it = swap_promise_list_.begin();
+  for (; it != swap_promise_list_.end(); it++) {
+    if ((*it) && ((*it)->type() == SwapPromise::SWAP_PROMISE_LATENCY_INFO)) {
+      latency_info->MergeWith(
+          (static_cast<LatencyInfoSwapPromise*>(*it))->GetLatencyInfo());
+    }
+  }
 }
 
 void LayerTreeImpl::QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise) {