Content Renderer FrameSwapMessageQueue: Fix DidActivate with DidNotSwap.

content/renderer/gpu/frame_swap_message_queue_unittest.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/frame_swap_message_queue.h"
 
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "ipc/ipc_message.h"
@@ skipping 270 matching lines @@
 TEST_F(FrameSwapMessageQueueTest, TestDeletesQueuedVisualStateMessage) {
   bool message_deleted = false;
   QueueVisualStateMessage(1, base::MakeUnique<NotifiesDeletionMessage>(
                                  &message_deleted, first_message_));
   queue_->DidActivate(1);
   queue_->DidSwap(1);
   queue_ = NULL;
   ASSERT_TRUE(message_deleted);
 }
 
+TEST_F(FrameSwapMessageQueueTest, TestDrainsMessageOnActivationThanDidNotSwap) {
+  const int frame = 6;
+  std::unique_ptr<IPC::Message> msg = CloneMessage(first_message_);
+  IPC::Message* msgSent = msg.get();
+  QueueVisualStateMessage(frame, std::move(msg));
+  queue_->DidActivate(frame);
+  EXPECT_TRUE(!queue_->Empty());
+
+  std::vector<std::unique_ptr<IPC::Message>> messages;
+  queue_->DidNotSwap(frame, cc::SwapPromise::SWAP_FAILS, &messages);
+  CHECK_EQ(1UL, messages.size());
+  EXPECT_EQ(messages[0].get(), msgSent);
+  msgSent = nullptr;
+
+  queue_ = nullptr;
+}
+
 }  // namespace content