Track renderer crash detected on WebState via GlobalWebStateObserver

ios/chrome/browser/metrics/ios_chrome_stability_metrics_provider.mm

 // Copyright 2015 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 "ios/chrome/browser/metrics/ios_chrome_stability_metrics_provider.h"
 
+#import "ios/web/public/web_state/web_state.h"
+
 IOSChromeStabilityMetricsProvider::IOSChromeStabilityMetricsProvider(
     PrefService* local_state)
     : helper_(local_state), recording_enabled_(false) {}
 
 IOSChromeStabilityMetricsProvider::~IOSChromeStabilityMetricsProvider() {}
 
 void IOSChromeStabilityMetricsProvider::OnRecordingEnabled() {
   recording_enabled_ = true;
 }
 
@@ skipping 23 matching lines @@
                            dummy_termination_code);
 }
 
 void IOSChromeStabilityMetricsProvider::WebStateDidStartLoading(
     web::WebState* web_state) {
   if (!recording_enabled_)
     return;
 
   helper_.LogLoadStarted();
 }
+
+void IOSChromeStabilityMetricsProvider::RenderProcessGone(
+    web::WebState* web_state) {
+  if (!recording_enabled_)
+    return;
+  LogRendererCrash();
+  // TODO(crbug.com/685649): Logs web_state->GetLastCommittedURL().

[Eugene But (OOO till 7-30), 2017/03/24 15:37:50]

Really nit: s/Logs/Log

[pkl (ping after 24h if needed), 2017/03/27 15:32:47]

Expanded the comment rendering this irrelevant.

+}