Don't delete CopyOutputRequests when queueing a new Surface frame.

cc/surfaces/surface.cc

Index: cc/surfaces/surface.cc
diff --git a/cc/surfaces/surface.cc b/cc/surfaces/surface.cc
index 6f482f56eb0c7ca96c35f28a44c54f2ecd3f01a5..81839aecca0939fbc271a12411ec266f8bea09d6 100644
--- a/cc/surfaces/surface.cc
+++ b/cc/surfaces/surface.cc
@@ -32,6 +32,8 @@ Surface::Surface(const SurfaceId& id, base::WeakPtr<SurfaceFactory> factory)
 
 Surface::~Surface() {
   ClearCopyRequests();

[danakj, 2017/02/23 22:52:28]

Can you change this things name maybe so it doesn't look as redundant with the
new code below?

+  for (auto& request : copy_requests_)
+    request->SendEmptyResult();
   if (factory_) {
     if (pending_frame_)
       UnrefFrameResources(*pending_frame_);
@@ -101,21 +103,18 @@ void Surface::RequestCopyOfOutput(
     return;
   }
 
-  std::vector<std::unique_ptr<CopyOutputRequest>>& copy_requests =
-      active_frame_->render_pass_list.back()->copy_requests;
-
   if (copy_request->has_source()) {
     const base::UnguessableToken& source = copy_request->source();
     // Remove existing CopyOutputRequests made on the Surface by the same
     // source.
     auto to_remove =
-        std::remove_if(copy_requests.begin(), copy_requests.end(),
+        std::remove_if(copy_requests_.begin(), copy_requests_.end(),
                        [&source](const std::unique_ptr<CopyOutputRequest>& x) {
                          return x->has_source() && x->source() == source;
                        });
-    copy_requests.erase(to_remove, copy_requests.end());
+    copy_requests_.erase(to_remove, copy_requests_.end());
   }
-  copy_requests.push_back(std::move(copy_request));
+  copy_requests_.push_back(std::move(copy_request));
 }
 
 void Surface::NotifySurfaceIdAvailable(const SurfaceId& surface_id) {
@@ -252,6 +251,18 @@ void Surface::TakeCopyOutputRequests(
     }
     render_pass->copy_requests.clear();
   }
+
+  if (active_frame_->render_pass_list.size() > 0) {
+    int root_pass_id = active_frame_->render_pass_list.back()->id;
+    for (auto& request : copy_requests_) {
+      copy_requests->insert(std::make_pair(root_pass_id, std::move(request)));
+    }
+    copy_requests_.clear();
+  } else {
+    for (auto& request : copy_requests_)
+      request->SendEmptyResult();
+    copy_requests_.clear();
+  }
 }
 
 const CompositorFrame& Surface::GetActiveFrame() const {