Use TimeTicks as much as possible in startup_metric_utils.

BUG=544131, 521164

Review URL: https://codereview.chromium.org/1425263003

Cr-Commit-Position: refs/heads/master@{#359183}

3 files changed, 9 insertions, 8 deletions

diff --git a/mandoline/ui/desktop_ui/browser_manager.cc b/mandoline/ui/desktop_ui/browser_manager.cc
index bef4dd5..3cb2b69 100644
--- a/mandoline/ui/desktop_ui/browser_manager.cc
+++ b/mandoline/ui/desktop_ui/browser_manager.cc
@@ -18,7 +18,7 @@ const char kGoogleURL[] = "http://www.google.com";
 }  // namespace
 
 BrowserManager::BrowserManager()
-    : app_(nullptr), startup_time_(base::Time::Now()) {}
+    : app_(nullptr), startup_ticks_(base::TimeTicks::Now()) {}
 
 BrowserManager::~BrowserManager() {
   while (!browsers_.empty())
diff --git a/mandoline/ui/desktop_ui/browser_manager.h b/mandoline/ui/desktop_ui/browser_manager.h
index 88ed3fa..6eee78f 100644
--- a/mandoline/ui/desktop_ui/browser_manager.h
+++ b/mandoline/ui/desktop_ui/browser_manager.h
@@ -37,7 +37,7 @@ class BrowserManager : public mojo::ApplicationDelegate,
   void BrowserWindowClosed(BrowserWindow* browser);
 
   // Get the time recorded just before the application message loop was started.
-  const base::Time& startup_time() const { return startup_time_; }
+  const base::TimeTicks& startup_ticks() const { return startup_ticks_; }
 
  private:
   // Overridden from LaunchHandler:
@@ -56,7 +56,7 @@ class BrowserManager : public mojo::ApplicationDelegate,
   mus::mojom::WindowTreeHostFactoryPtr host_factory_;
   mojo::WeakBindingSet<LaunchHandler> launch_handler_bindings_;
   std::set<BrowserWindow*> browsers_;
-  base::Time startup_time_;
+  const base::TimeTicks startup_ticks_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserManager);
 };
diff --git a/mandoline/ui/desktop_ui/browser_window.cc b/mandoline/ui/desktop_ui/browser_window.cc
index 2b4ad48..a78e60e 100644
--- a/mandoline/ui/desktop_ui/browser_window.cc
+++ b/mandoline/ui/desktop_ui/browser_window.cc
@@ -170,7 +170,7 @@ void BrowserWindow::OnEmbed(mus::Window* root) {
   CHECK(!root_);
 
   // Record when the browser window was displayed, used for performance testing.
-  const base::Time display_time = base::Time::Now();
+  const base::TimeTicks display_ticks = base::TimeTicks::Now();
 
   root_ = root;
 
@@ -214,7 +214,8 @@ void BrowserWindow::OnEmbed(mus::Window* root) {
   LoadURL(default_url_);
 
   // Record the time spent opening initial tabs, used for performance testing.
-  const base::TimeDelta open_tabs_delta = base::Time::Now() - display_time;
+  const base::TimeDelta open_tabs_delta =
+      base::TimeTicks::Now() - display_ticks;
 
   // Record the browser startup time metrics, used for performance testing.
   static bool recorded_browser_startup_metrics = false;
@@ -225,10 +226,10 @@ void BrowserWindow::OnEmbed(mus::Window* root) {
     request->url = mojo::String::From("mojo:tracing");
     tracing::StartupPerformanceDataCollectorPtr collector;
     app_->ConnectToService(request.Pass(), &collector);
-    collector->SetBrowserWindowDisplayTime(display_time.ToInternalValue());
+    collector->SetBrowserWindowDisplayTicks(display_ticks.ToInternalValue());
     collector->SetBrowserOpenTabsTimeDelta(open_tabs_delta.ToInternalValue());
-    collector->SetBrowserMessageLoopStartTime(
-        manager_->startup_time().ToInternalValue());
+    collector->SetBrowserMessageLoopStartTicks(
+        manager_->startup_ticks().ToInternalValue());
     recorded_browser_startup_metrics = true;
   }
 }