Add SwapPromise support to LayerTreeHost and LayerTreeImpl

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 4604043663920750438b5de260b0d8a0249d36b2..aa923cb77382469d2c889ec52fdcf47148a16b9b 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -17,6 +17,10 @@
 #include "ui/gfx/size_conversions.h"
 #include "ui/gfx/vector2d_conversions.h"
 
+namespace {
+const size_t kMaxQueuedSwapPromiseNumber = 100;
+}  // namespace
+
 namespace cc {
 
 LayerTreeImpl::LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl)
@@ -119,6 +123,9 @@ void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
 
   target_tree->SetLatencyInfo(latency_info_);
   latency_info_.Clear();
+
+  target_tree->TakeSwapPromise(&swap_promise_list_);
+
   target_tree->SetPageScaleFactorAndLimits(
       page_scale_factor(), min_page_scale_factor(), max_page_scale_factor());
   target_tree->SetPageScaleDelta(
@@ -696,6 +703,36 @@ void LayerTreeImpl::ClearLatencyInfo() {
   latency_info_.Clear();
 }
 
+void LayerTreeImpl::QueueSwapPromise(const SwapPromise& swap_promise) {
+  if (swap_promise_list_.size() > kMaxQueuedSwapPromiseNumber) {
+    NOTREACHED() << "LayerTreeImpl::swap_promise_list overflows";
+    swap_promise_list_.clear();
+  }
+  swap_promise_list_.push_back(swap_promise);
+}
+
+void LayerTreeImpl::TakeSwapPromise(
+    std::vector<SwapPromise>* new_swap_promise) {
+  swap_promise_list_.insert(swap_promise_list_.end(),
+                            new_swap_promise->begin(),
+                            new_swap_promise->end());
+  new_swap_promise->clear();
+}
+
+void LayerTreeImpl::FinishSwapPromise() {
+  for (size_t i = 0; i < swap_promise_list_.size(); i++) {
+    swap_promise_list_[i].did_swap_callback.Run();
+  }
+  swap_promise_list_.clear();
+}
+
+void LayerTreeImpl::BreakSwapPromise(const std::string& msg) {
+  for (size_t i = 0; i < swap_promise_list_.size(); i++) {
+    swap_promise_list_[i].swap_aborted_callback.Run(msg);
+  }
+  swap_promise_list_.clear();
+}
+
 void LayerTreeImpl::DidModifyTilePriorities() {
   layer_tree_host_impl_->DidModifyTilePriorities();
 }