Disable the hang dialog detector when showModalDialog is running.

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 <utility>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
@@ skipping 887 matching lines @@
 
   // Any non-wheel input event cancels pending wheel events.
   if (input_event.type != WebInputEvent::MouseWheel)
     coalesced_mouse_wheel_events_.clear();
 
   // Any input event cancels a pending mouse move event. Note that
   // |next_mouse_move_| possibly owns |input_event|, so don't use |input_event|
   // after this line.
   next_mouse_move_.reset();
 
-  in_flight_event_count_++;
+  increment_in_flight_event_count();
   StartHangMonitorTimeout(
       TimeDelta::FromMilliseconds(hung_renderer_delay_ms_));
 }
 
 void RenderWidgetHostImpl::ForwardTouchEvent(
     const WebKit::WebTouchEvent& touch_event) {
   TRACE_EVENT0("renderer_host", "RenderWidgetHostImpl::ForwardTouchEvent");
   if (ignore_input_events_ || process_->IgnoreInputEvents())
     return;
 
@@ skipping 445 matching lines @@
 
 void RenderWidgetHostImpl::OnMsgInputEventAck(WebInputEvent::Type event_type,
                                               bool processed) {
   TRACE_EVENT0("renderer_host", "RenderWidgetHostImpl::OnMsgInputEventAck");
 
   // Log the time delta for processing an input event.
   TimeDelta delta = TimeTicks::Now() - input_event_start_time_;
   UMA_HISTOGRAM_TIMES("MPArch.RWH_InputEventDelta", delta);
 
   // Cancel pending hung renderer checks since the renderer is responsive.
-  if (--in_flight_event_count_ == 0)
+  if (decrement_in_flight_event_count() == 0)
     StopHangMonitorTimeout();
 
   int type = static_cast<int>(event_type);
   if (type < WebInputEvent::Undefined) {
     RecordAction(UserMetricsAction("BadMessageTerminate_RWH2"));
     process_->ReceivedBadMessage();
   } else if (type == WebInputEvent::MouseMove) {
     mouse_move_pending_ = false;
 
     // now, we can send the next mouse move event
@@ skipping 395 matching lines @@
   // indicate that no callback is in progress (i.e. without this line
   // DelayedAutoResized will not get called again).
   new_auto_size_.SetSize(0, 0);
   if (!should_auto_resize_)
     return;
 
   OnRenderAutoResized(new_size);
 }
 
 }  // namespace content