Hang Monitor UMA

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 <tuple>
@@ skipping 943 matching lines @@
   repaint_ack_pending_ = true;
   TRACE_EVENT_ASYNC_BEGIN0(
       "renderer_host", "RenderWidgetHostImpl::repaint_ack_pending_", this);
   Send(new ViewMsg_Repaint(routing_id_, current_size_));
   return true;
 }
 
 void RenderWidgetHostImpl::StartHangMonitorTimeout(
     base::TimeDelta delay,
     blink::WebInputEvent::Type event_type) {
+  if (hang_start_time_.is_null())
+    hang_start_time_ = TimeTicks::Now();
   if (!hang_monitor_timeout_)
     return;
   if (!hang_monitor_timeout_->IsRunning())
     hang_monitor_event_type_ = event_type;
   last_event_type_ = event_type;
   hang_monitor_timeout_->Start(delay);
 }
 
 void RenderWidgetHostImpl::RestartHangMonitorTimeoutIfNecessary() {
-  if (!hang_monitor_timeout_)
-    return;
-  if (in_flight_event_count_ > 0 && !is_hidden_)
-    hang_monitor_timeout_->Restart(hung_renderer_delay_);
+  if (in_flight_event_count_ > 0 && !is_hidden_) {
+    if (!hang_start_time_.is_null())

[Ilya Sherman, 2017/03/24 21:16:19]

nit: Please use curly braces, since the body of this if-stmt spans multiple
lines of text.

+      UMA_HISTOGRAM_TIMES("MPArch.RWH_HangMonitorUnresponsive",
+                          TimeTicks::Now() - hang_start_time_);
+    hang_start_time_ = TimeTicks::Now();
+    if (hang_monitor_timeout_)
+      hang_monitor_timeout_->Restart(hung_renderer_delay_);
+  }
 }
 
 void RenderWidgetHostImpl::DisableHangMonitorForTesting() {
   StopHangMonitorTimeout();
   hang_monitor_timeout_.reset();
 }
 
 void RenderWidgetHostImpl::StopHangMonitorTimeout() {
+  if (!hang_start_time_.is_null())
+    UMA_HISTOGRAM_TIMES("MPArch.RWH_HangMonitorUnresponsive",
+                        TimeTicks::Now() - hang_start_time_);
+  hang_start_time_ = TimeTicks();

[Ilya Sherman, 2017/03/24 21:16:19]

Could you please factor out these four lines of shared code into a small helper
function?

   if (hang_monitor_timeout_)
     hang_monitor_timeout_->Stop();
   RendererIsResponsive();
 }
 
 void RenderWidgetHostImpl::StartNewContentRenderingTimeout(
     uint32_t next_source_id) {
   current_content_source_id_ = next_source_id;
   // 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
@@ skipping 1634 matching lines @@
 void RenderWidgetHostImpl::RequestCompositionUpdates(bool immediate_request,
                                                      bool monitor_updates) {
   if (!immediate_request && monitor_updates == monitoring_composition_info_)
     return;
   monitoring_composition_info_ = monitor_updates;
   Send(new InputMsg_RequestCompositionUpdates(routing_id_, immediate_request,
                                               monitor_updates));
 }
 
 }  // namespace content