Make unload tests stable.

content/browser/renderer_host/render_widget_host_impl.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 "content/browser/renderer_host/render_widget_host_impl.h"
 
 #include <math.h>
 
 #include <set>
 #include <utility>
@@ skipping 897 matching lines @@
 void RenderWidgetHostImpl::StartHangMonitorTimeout(base::TimeDelta delay) {
   if (hang_monitor_timeout_)
     hang_monitor_timeout_->Start(delay);
 }
 
 void RenderWidgetHostImpl::RestartHangMonitorTimeout() {
   if (hang_monitor_timeout_)
     hang_monitor_timeout_->Restart(hung_renderer_delay_);
 }
 
+void RenderWidgetHostImpl::DisableHangMonitorForTest() {
+  StopHangMonitorTimeout();
+  hang_monitor_timeout_.reset();

[Charlie Reis, 2016/05/23 17:03:30]

Yeah, I think this should be sufficient for this test.  We also have
RenderFrameHostImpl::DisableSwapOutTimerForTesting, but I don't think that's
necessary here because the swapout/unload event won't ever show dialogs.

nit: Maybe change the name from ForTest() to ForTesting() to be consistent (and
since there's a lot more of the latter in the codebase).

+}
+
 void RenderWidgetHostImpl::StopHangMonitorTimeout() {
   if (hang_monitor_timeout_)
     hang_monitor_timeout_->Stop();
   RendererIsResponsive();
 }
 
 void RenderWidgetHostImpl::StartNewContentRenderingTimeout() {
   // It is possible for a compositor frame to arrive before the browser is
   // notified about the page being committed, in which case no timer is
   // necessary.
@@ skipping 1223 matching lines @@
   return delegate_ ? delegate_->GetRootBrowserAccessibilityManager() : NULL;
 }
 
 BrowserAccessibilityManager*
     RenderWidgetHostImpl::GetOrCreateRootBrowserAccessibilityManager() {
   return delegate_ ?
       delegate_->GetOrCreateRootBrowserAccessibilityManager() : NULL;
 }
 
 }  // namespace content