Make rendering timeouts work even if paint data received early

content/browser/renderer_host/render_widget_host_unittest.cc

 // Copyright (c) 2012 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 "base/basictypes.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 1088 matching lines @@
 }
 
 // Test that the rendering timeout for newly loaded content fires
 // when enough time passes without receiving a new compositor frame.
 TEST_F(RenderWidgetHostTest, NewContentRenderingTimeout) {
   host_->set_new_content_rendering_delay_for_testing(
       base::TimeDelta::FromMicroseconds(10));
 
   // Test immediate start and stop, ensuring that the timeout doesn't fire.
   host_->StartNewContentRenderingTimeout();
-  host_->StopNewContentRenderingTimeout();
+  host_->OnFirstPaintAfterLoad();
   base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
       FROM_HERE, base::MessageLoop::QuitClosure(),
       TimeDelta::FromMicroseconds(20));

[esprehn, 2015/10/02 05:58:15]

Why wait 20 microseconds? This usually produces flake in tests

[kenrb, 2015/10/02 13:24:40]

I used the same values as the hung renderer test, but I've changed it to 200.

+  base::MessageLoop::current()->Run();
+
+  EXPECT_FALSE(host_->new_content_rendering_timeout_fired());
+
+  // Test that the timer doesn't fire if it receives a stop before
+  // a start.
+  host_->OnFirstPaintAfterLoad();
+  host_->StartNewContentRenderingTimeout();
+  base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+      FROM_HERE, base::MessageLoop::QuitClosure(),
+      TimeDelta::FromMicroseconds(20));
   base::MessageLoop::current()->Run();
 
   EXPECT_FALSE(host_->new_content_rendering_timeout_fired());
 
   // Test with a long delay to ensure that it does fire this time.
   host_->StartNewContentRenderingTimeout();
   base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
       FROM_HERE, base::MessageLoop::QuitClosure(),
       TimeDelta::FromMicroseconds(20));
   base::MessageLoop::current()->Run();
@@ skipping 456 matching lines @@
   // Having an initial size set means that the size information had been sent
   // with the reqiest to new up the RenderView and so subsequent WasResized
   // calls should not result in new IPC (unless the size has actually changed).
   host_->WasResized();
   EXPECT_FALSE(process_->sink().GetUniqueMessageMatching(ViewMsg_Resize::ID));
   EXPECT_EQ(initial_size_, host_->old_resize_params_->new_size);
   EXPECT_TRUE(host_->resize_ack_pending_);
 }
 
 }  // namespace content