Queue latency info swap promises in a separate already-active queue.

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 583d94219d1d9c2a3bd6ca8a5825fc861d3a7ed9..2b8f993a8966327f83c226777cbfba1c293e3f81 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -1031,6 +1031,11 @@ void LayerTreeImpl::AsValueInto(base::trace_event::TracedValue* state) const {
   for (auto* swap_promise : swap_promise_list_)
     state->AppendDouble(swap_promise->TraceId());
   state->EndArray();
+
+  state->BeginArray("active_tree_swap_promise_trace_ids");
+  for (auto* swap_promise : active_tree_swap_promise_list_)
+    state->AppendDouble(swap_promise->TraceId());
+  state->EndArray();
 }
 
 void LayerTreeImpl::SetRootLayerScrollOffsetDelegate(
@@ -1108,23 +1113,34 @@ void LayerTreeImpl::QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise) {
   swap_promise_list_.push_back(swap_promise.Pass());
 }
 
+void LayerTreeImpl::QueueActiveTreeSwapPromise(
+    scoped_ptr<SwapPromise> swap_promise) {
+  DCHECK(swap_promise);
+  active_tree_swap_promise_list_.push_back(swap_promise.Pass());
+}
+
 void LayerTreeImpl::PassSwapPromises(
     ScopedPtrVector<SwapPromise>* new_swap_promise) {
-  swap_promise_list_.insert_and_take(swap_promise_list_.end(),
-                                     new_swap_promise);
-  new_swap_promise->clear();
+  BreakSwapPromises(SwapPromise::SWAP_FAILS);

[danakj, 2015/08/14 17:47:39]

add a comment explaining what's going on? doesn't this break active tree ones
too which was your goal to avoid?

[Tobias Sargeant, 2015/08/18 11:22:15]

Yes, you're right. Corrected now.

+  swap_promise_list_.swap(*new_swap_promise);
 }
 
 void LayerTreeImpl::FinishSwapPromises(CompositorFrameMetadata* metadata) {
   for (auto* swap_promise : swap_promise_list_)
     swap_promise->DidSwap(metadata);
   swap_promise_list_.clear();
+  for (auto* swap_promise : active_tree_swap_promise_list_)
+    swap_promise->DidSwap(metadata);
+  active_tree_swap_promise_list_.clear();
 }
 
 void LayerTreeImpl::BreakSwapPromises(SwapPromise::DidNotSwapReason reason) {
   for (auto* swap_promise : swap_promise_list_)
     swap_promise->DidNotSwap(reason);
   swap_promise_list_.clear();
+  for (auto* swap_promise : active_tree_swap_promise_list_)
+    swap_promise->DidNotSwap(reason);
+  active_tree_swap_promise_list_.clear();
 }
 
 void LayerTreeImpl::DidModifyTilePriorities() {