Add a histogram to measure browser window display

chrome/browser/ui/browser.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/ui/browser.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <shellapi.h>
 #endif  // OS_WIN
 
 #include <algorithm>
 #include <string>
 
 #include "base/base_paths.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
+#include "base/process_info.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/autofill/personal_data_manager_factory.h"
 #include "chrome/browser/background/background_contents_service.h"
@@ skipping 1939 matching lines @@
 
 bool Browser::IsMouseLocked() const {
   return fullscreen_controller_->IsMouseLocked();
 }
 
 void Browser::OnWindowDidShow() {
   if (window_has_shown_)
     return;
   window_has_shown_ = true;
 
+// CurrentProcessInfo::CreationTime() is currently only implemented on Mac and
+// Windows.
+#if defined(OS_MACOSX) || defined(OS_WIN)

[sky, 2012/06/26 16:14:15]

Aren't there a number of code paths that could result in showing non-browser
things for any length of time that end up skewing this number to be meaningless?

+  // Measure the latency from startup till the first browser window becomes
+  // visible.
+  static bool isFirstBrowserWindow = true;
+  if (isFirstBrowserWindow) {
+    isFirstBrowserWindow = false;
+    const base::Time* process_creation_time =
+        base::CurrentProcessInfo::CreationTime();
+
+    if (process_creation_time) {
+      UMA_HISTOGRAM_LONG_TIMES(
+          "Startup.BrowserWindowDisplay",
+          base::Time::Now() - *process_creation_time);
+    }
+  }
+#endif // OS_MACOSX || OS_WIN
+
   // Nothing to do for non-tabbed windows.
   if (!is_type_tabbed())
     return;
 
   // Show any pending global error bubble.
   GlobalErrorService* service =
       GlobalErrorServiceFactory::GetForProfile(profile());
   GlobalError* error = service->GetFirstGlobalErrorWithBubbleView();
   if (error)
     error->ShowBubbleView(this);
@@ skipping 1908 matching lines @@
   if (contents && !allow_js_access) {
     contents->web_contents()->GetController().LoadURL(
         target_url,
         content::Referrer(),
         content::PAGE_TRANSITION_LINK,
         std::string());  // No extra headers.
   }
 
   return contents != NULL;
 }