Consolidate startup_metric_utils BrowserOpenTabs code.

Add startup_metric_utils::RecordBrowserOpenTabsDelta() helper.
Record a (reasonably corresponding?) time delta in Mandoline.
Change mojo:tracing to record a time delta instead of a timestamp.
Minor cleanup in chrome_browser_main.cc.

BUG=513779
TEST="./tools/perf/run_benchmark --browser=mandoline-debug startup.warm.blank_page" reports an 'open tabs time' closer to Chrome's.
R=sky@chromium.org,gab@chromium.org

Review URL: https://codereview.chromium.org/1315263002

Cr-Commit-Position: refs/heads/master@{#346021}

8 files changed, 31 insertions, 29 deletions

diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 51500ea..c2c662e 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -1610,13 +1610,12 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
 
   // We are in regular browser boot sequence. Open initial tabs and enter the
   // main message loop.
-#if defined(OS_CHROMEOS)
+  std::vector<Profile*> last_opened_profiles;
+#if !defined(OS_CHROMEOS)
   // On ChromeOS multiple profiles doesn't apply, and will break if we load
   // them this early as the cryptohome hasn't yet been mounted (which happens
-  // only once we log in.
-  std::vector<Profile*> last_opened_profiles;
-#else
-  std::vector<Profile*> last_opened_profiles =
+  // only once we log in).
+  last_opened_profiles =
       g_browser_process->profile_manager()->GetLastOpenedProfiles();
 #endif  // defined(OS_CHROMEOS)
 
@@ -1625,7 +1624,7 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
 
   // This step is costly and is already measured in
   // Startup.StartupBrowserCreator_Start.
-  bool started = browser_creator_->Start(
+  const bool started = browser_creator_->Start(
       parsed_command_line(), base::FilePath(), profile_, last_opened_profiles);
   const base::TimeTicks start_time_step3 = base::TimeTicks::Now();
   if (started) {
@@ -1655,8 +1654,8 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
       parameters().autorelease_pool->Recycle();
 #endif  // defined(OS_MACOSX)
 
-    base::TimeDelta delay = base::TimeTicks::Now() - browser_open_start;
-    UMA_HISTOGRAM_LONG_TIMES_100("Startup.BrowserOpenTabs", delay);
+    const base::TimeDelta delta = base::TimeTicks::Now() - browser_open_start;
+    startup_metric_utils::RecordBrowserOpenTabsDelta(delta);
 
     // If we're running tests (ui_task is non-null), then we don't want to
     // call RequestLanguageList or StartRepeatedVariationsSeedFetch or
@@ -1671,11 +1670,8 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
       translate::TranslateDownloadManager::RequestLanguageList(
           profile_->GetPrefs());
     }
-
-    run_message_loop_ = true;
-  } else {
-    run_message_loop_ = false;
   }
+  run_message_loop_ = started;
   browser_creator_.reset();
 
 #if !defined(OS_LINUX) || defined(OS_CHROMEOS)  // http://crbug.com/426393
diff --git a/components/html_viewer/stats_collection_controller.cc b/components/html_viewer/stats_collection_controller.cc
index 725ecc4..d519dde 100644
--- a/components/html_viewer/stats_collection_controller.cc
+++ b/components/html_viewer/stats_collection_controller.cc
@@ -42,14 +42,8 @@ void GetStartupPerformanceTimesCallbackImpl(
   startup_metric_utils::RecordBrowserWindowDisplay(
       base::Time::FromInternalValue(times->browser_window_display_time));
 
-  // TODO(msw): Consolidate with chrome's PreMainMessageLoopRunImpl()...
-  // TODO(msw): Need to measure the "browser_open_start" time for this delta...
-  const base::Time browser_open_start =
-      base::Time::FromInternalValue(times->shell_process_creation_time);
-  const base::Time browser_open_tabs_time =
-      base::Time::FromInternalValue(times->browser_open_tabs_time);
-  base::TimeDelta delta = browser_open_tabs_time - browser_open_start;
-  UMA_HISTOGRAM_LONG_TIMES_100("Startup.BrowserOpenTabs", delta);
+  startup_metric_utils::RecordBrowserOpenTabsDelta(
+      base::TimeDelta::FromInternalValue(times->browser_open_tabs_time_delta));
 
   startup_metric_utils::RecordFirstWebContentsMainFrameLoad(
       base::Time::FromInternalValue(
diff --git a/components/startup_metric_utils/startup_metric_utils.cc b/components/startup_metric_utils/startup_metric_utils.cc
index e3530a2..00ddf35 100644
--- a/components/startup_metric_utils/startup_metric_utils.cc
+++ b/components/startup_metric_utils/startup_metric_utils.cc
@@ -315,6 +315,15 @@ void RecordBrowserWindowDisplay(const base::Time& time) {
                            time - g_process_creation_time.Get());
 }
 
+void RecordBrowserOpenTabsDelta(const base::TimeDelta& delta) {
+  static bool is_first_call = true;
+  if (!is_first_call)
+    return;
+  is_first_call = false;
+
+  UMA_HISTOGRAM_LONG_TIMES_100("Startup.BrowserOpenTabs", delta);
+}
+
 void RecordFirstWebContentsMainFrameLoad(const base::Time& time) {
   static bool is_first_call = true;
   if (!is_first_call || time.is_null())
diff --git a/components/startup_metric_utils/startup_metric_utils.h b/components/startup_metric_utils/startup_metric_utils.h
index 38e695e..2c59f6e 100644
--- a/components/startup_metric_utils/startup_metric_utils.h
+++ b/components/startup_metric_utils/startup_metric_utils.h
@@ -48,6 +48,9 @@ void RecordBrowserMainMessageLoopStart(const base::Time& time,
 // Call this with the time when the first browser window became visible.
 void RecordBrowserWindowDisplay(const base::Time& time);
 
+// Call this with the time delta that the browser spent opening its tabs.
+void RecordBrowserOpenTabsDelta(const base::TimeDelta& delta);
+
 // Call this with the time when the first web contents loaded its main frame.
 void RecordFirstWebContentsMainFrameLoad(const base::Time& time);
 
diff --git a/mandoline/ui/desktop_ui/browser_window.cc b/mandoline/ui/desktop_ui/browser_window.cc
index ec3eed9..198d5ad 100644
--- a/mandoline/ui/desktop_ui/browser_window.cc
+++ b/mandoline/ui/desktop_ui/browser_window.cc
@@ -132,8 +132,8 @@ void BrowserWindow::OnEmbed(mojo::View* root) {
     Embed(request.Pass());
   }
 
-  // Record when the initial 'tabs' were opened, used for performance testing.
-  const base::Time open_tabs_time = base::Time::Now();
+  // Record the time spent opening initial tabs, used for performance testing.
+  const base::TimeDelta open_tabs_delta = base::Time::Now() - display_time;
 
   // Record the browser startup time metrics, used for performance testing.
   static bool recorded_browser_startup_metrics = false;
@@ -145,7 +145,7 @@ void BrowserWindow::OnEmbed(mojo::View* root) {
     tracing::StartupPerformanceDataCollectorPtr collector;
     app_->ConnectToService(request.Pass(), &collector);
     collector->SetBrowserWindowDisplayTime(display_time.ToInternalValue());
-    collector->SetBrowserOpenTabsTime(open_tabs_time.ToInternalValue());
+    collector->SetBrowserOpenTabsTimeDelta(open_tabs_delta.ToInternalValue());
     collector->SetBrowserMessageLoopStartTime(
         manager_->startup_time().ToInternalValue());
     recorded_browser_startup_metrics = true;
diff --git a/mojo/services/tracing/public/interfaces/tracing.mojom b/mojo/services/tracing/public/interfaces/tracing.mojom
index 935a862..6dbed2a 100644
--- a/mojo/services/tracing/public/interfaces/tracing.mojom
+++ b/mojo/services/tracing/public/interfaces/tracing.mojom
@@ -35,7 +35,7 @@ struct StartupPerformanceTimes {
   int64 shell_main_entry_point_time;
   int64 browser_message_loop_start_time;
   int64 browser_window_display_time;
-  int64 browser_open_tabs_time;
+  int64 browser_open_tabs_time_delta;
   // TODO(msw): Rename to avoid "web contents"?
   int64 first_web_contents_main_frame_load_time;
   // TODO(msw): Rename to match "FirstWebContents.NonEmptyPaint" metric?
@@ -49,7 +49,7 @@ interface StartupPerformanceDataCollector {
   SetShellMainEntryPointTime(int64 time);
   SetBrowserMessageLoopStartTime(int64 time);
   SetBrowserWindowDisplayTime(int64 time);
-  SetBrowserOpenTabsTime(int64 time);
+  SetBrowserOpenTabsTimeDelta(int64 delta);
   SetFirstWebContentsMainFrameLoadTime(int64 time);
   SetFirstVisuallyNonEmptyLayoutTime(int64 time);
 
diff --git a/mojo/services/tracing/tracing_app.cc b/mojo/services/tracing/tracing_app.cc
index 504ba2c..d01cf37 100644
--- a/mojo/services/tracing/tracing_app.cc
+++ b/mojo/services/tracing/tracing_app.cc
@@ -109,9 +109,9 @@ void TracingApp::SetBrowserWindowDisplayTime(int64 time) {
     startup_performance_times_.browser_window_display_time = time;
 }
 
-void TracingApp::SetBrowserOpenTabsTime(int64 time) {
-  if (startup_performance_times_.browser_open_tabs_time == 0)
-    startup_performance_times_.browser_open_tabs_time = time;
+void TracingApp::SetBrowserOpenTabsTimeDelta(int64 delta) {
+  if (startup_performance_times_.browser_open_tabs_time_delta == 0)
+    startup_performance_times_.browser_open_tabs_time_delta = delta;
 }
 
 void TracingApp::SetFirstWebContentsMainFrameLoadTime(int64 time) {
diff --git a/mojo/services/tracing/tracing_app.h b/mojo/services/tracing/tracing_app.h
index 8d0ff2b..37a0331 100644
--- a/mojo/services/tracing/tracing_app.h
+++ b/mojo/services/tracing/tracing_app.h
@@ -52,7 +52,7 @@ class TracingApp
   void SetShellMainEntryPointTime(int64 time) override;
   void SetBrowserMessageLoopStartTime(int64 time) override;
   void SetBrowserWindowDisplayTime(int64 time) override;
-  void SetBrowserOpenTabsTime(int64 time) override;
+  void SetBrowserOpenTabsTimeDelta(int64 delta) override;
   void SetFirstWebContentsMainFrameLoadTime(int64 time) override;
   void SetFirstVisuallyNonEmptyLayoutTime(int64 time) override;
   void GetStartupPerformanceTimes(