Flapper field trial to use workerpool for sync file operations.

content/browser/web_contents/web_contents_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/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
+#include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/stats_counters.h"
 #include "base/string16.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "base/sys_info.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "content/browser/browser_plugin/browser_plugin_embedder.h"
 #include "content/browser/browser_plugin/browser_plugin_guest.h"
@@ skipping 2306 matching lines @@
 void WebContentsImpl::OnSetSelectedColorInColorChooser(int color_chooser_id,
                                                        SkColor color) {
   if (color_chooser_ &&
       color_chooser_id == color_chooser_->identifier())
     color_chooser_->SetSelectedColor(color);
 }
 
 void WebContentsImpl::OnPepperPluginHung(int plugin_child_id,
                                          const FilePath& path,
                                          bool is_hung) {
+  HISTOGRAM_COUNTS("Pepper.PluginHung", 1);
+
+  // Determine how often hangs happen when using worker pool versus
+  // FILE thread.  kFieldTrialName needs to match the value in
+  // pepper_file_message_filter.cc, but plumbing that through would be
+  // disruptive for temporary code.
+  // TODO(shess): Remove once the workpool is proven superior.
+  // http://crbug.com/153383
+  static const char* const kFieldTrialName = "FlapperIOThread";
+  static const bool hung_trial_exists =
+      base::FieldTrialList::TrialExists(kFieldTrialName);
+  if (hung_trial_exists) {
+    HISTOGRAM_COUNTS(base::FieldTrial::MakeName("Pepper.PluginHung",
+                                                kFieldTrialName), 1);
+  }
+
   FOR_EACH_OBSERVER(WebContentsObserver, observers_,
                     PluginHungStatusChanged(plugin_child_id, path, is_hung));
 }
 
 // This exists for render views that don't have a WebUI, but do have WebUI
 // bindings enabled.
 void WebContentsImpl::OnWebUISend(const GURL& source_url,
                                   const std::string& name,
                                   const base::ListValue& args) {
   if (delegate_)
@@ skipping 1044 matching lines @@
   }
 }
 
 content::BrowserPluginGuest* WebContentsImpl::GetBrowserPluginGuest() {
   return browser_plugin_guest_.get();
 }
 
 content::BrowserPluginEmbedder* WebContentsImpl::GetBrowserPluginEmbedder() {
   return browser_plugin_embedder_.get();
 }