Add Startup.BrowserView.FirstPaint / .CompositingEnded histograms.

chrome/browser/background/background_mode_manager.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 "chrome/browser/background/background_mode_manager.h"
 
 #include <stddef.h>
 #include <algorithm>
 #include <string>
 #include <utility>
@@ skipping 39 matching lines @@
 #include "chrome/browser/ui/user_manager.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/grit/chrome_unscaled_resources.h"
 #include "chrome/grit/chromium_strings.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
+#include "components/startup_metric_utils/browser/startup_metric_utils.h"
 #include "content/public/browser/notification_service.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/common/constants.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/manifest_handlers/options_page_info.h"
 #include "extensions/common/one_shot_event.h"
 #include "extensions/common/permissions/permission_set.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 
@@ skipping 640 matching lines @@
   }
 }
 
 void BackgroundModeManager::StartBackgroundMode() {
   DCHECK(ShouldBeInBackgroundMode());
   // Don't bother putting ourselves in background mode if we're already there
   // or if background mode is disabled.
   if (in_background_mode_)
     return;
 
+  startup_metric_utils::SetBackgroundModeEnabled();

[sky, 2017/04/11 17:13:36]

How come you don't need a matching End?

[themblsha, 2017/04/12 17:18:28]

The intent is to set this once per startup, as it could delay the normal
appearance of the first Browser window. The only way to 'end' this is to restart
the browser.

It would affect the unit_tests but they're out of scope of this problem anyway
since startup_metric_utils.cc already rely on global singletons and require the
tests to be inside browser_tests / interactive_ui_tests anyway.

+
   // Mark ourselves as running in background mode.
   in_background_mode_ = true;
 
   UpdateKeepAliveAndTrayIcon();
 
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_BACKGROUND_MODE_CHANGED,
       content::Source<BackgroundModeManager>(this),
       content::Details<bool>(&in_background_mode_));
 }
@@ skipping 317 matching lines @@
     }
   }
   return profile_it;
 }
 
 bool BackgroundModeManager::IsBackgroundModePrefEnabled() const {
   PrefService* service = g_browser_process->local_state();
   DCHECK(service);
   return service->GetBoolean(prefs::kBackgroundModeEnabled);
 }