Reland "Send FrameSwapMessageQueue's messages in QueueMessageSwapPromise" with fixes

content/renderer/gpu/queue_message_swap_promise.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/gpu/queue_message_swap_promise.h"
 
 #include "base/command_line.h"
+#include "content/common/view_messages.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/renderer/render_thread.h"
 #include "content/renderer/gpu/frame_swap_message_queue.h"
 #include "ipc/ipc_sync_message_filter.h"
 
 namespace content {
 
 QueueMessageSwapPromise::QueueMessageSwapPromise(
     scoped_refptr<IPC::SyncMessageFilter> message_sender,
     scoped_refptr<content::FrameSwapMessageQueue> message_queue,
@@ skipping 23 matching lines @@
 #endif
   message_queue_->DidActivate(source_frame_number_);
   // The OutputSurface will take care of the Drain+Send.
 }
 
 void QueueMessageSwapPromise::WillSwap(cc::CompositorFrameMetadata* metadata) {
 #if DCHECK_IS_ON()
   DCHECK(!completed_);
 #endif
   message_queue_->DidSwap(source_frame_number_);
-  // The OutputSurface will take care of the Drain+Send.
+
+  if (!message_queue_->AreFramesDiscarded()) {
+    std::unique_ptr<FrameSwapMessageQueue::SendMessageScope>
+        send_message_scope = message_queue_->AcquireSendMessageScope();
+    std::vector<std::unique_ptr<IPC::Message>> messages;
+    message_queue_->DrainMessages(&messages);
+    std::vector<IPC::Message> messages_to_send;
+    FrameSwapMessageQueue::TransferMessages(&messages, &messages_to_send);
+    if (!messages_to_send.empty()) {
+      metadata->frame_token = message_queue_->AllocateFrameToken();
+      message_sender_->Send(new ViewHostMsg_FrameSwapMessages(
+          message_queue_->routing_id(), metadata->frame_token,
+          messages_to_send));
+    }
+  }
+
   PromiseCompleted();
 }
 
 void QueueMessageSwapPromise::DidSwap() {}
 
 cc::SwapPromise::DidNotSwapAction QueueMessageSwapPromise::DidNotSwap(
     DidNotSwapReason reason) {
 #if DCHECK_IS_ON()
   DCHECK(!completed_);
 #endif
@@ skipping 12 matching lines @@
 #if DCHECK_IS_ON()
   completed_ = true;
 #endif
 }
 
 int64_t QueueMessageSwapPromise::TraceId() const {
   return 0;
 }
 
 }  // namespace content