Add .SingleTab and .MultiTabs suffix to Startup.FirstWebContents.MainNavigationStart histogram.

components/startup_metric_utils/browser/startup_metric_utils.h

 // Copyright 2013 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.
 
 #ifndef COMPONENTS_STARTUP_METRIC_UTILS_BROWSER_STARTUP_METRIC_UTILS_H_
 #define COMPONENTS_STARTUP_METRIC_UTILS_BROWSER_STARTUP_METRIC_UTILS_H_
 
 #include "base/time/time.h"
 
 class PrefRegistrySimple;
 class PrefService;
 
 // Utility functions to support metric collection for browser startup. Timings
 // should use TimeTicks whenever possible. OS-provided timings are still
 // received as Time out of cross-platform support necessity but are converted to
 // TimeTicks as soon as possible in an attempt to reduce the potential skew
 // between the two basis. See crbug.com/544131 for reasoning.
 
 namespace startup_metric_utils {
 
+// Identifies the workload of profiled WebContents, used to refine startup
+// metrics.
+enum class WebContentsWorkload {
+  // Only loading a single tab.
+  SINGLE_TAB,
+  // Loading multiple tabs (of which the profiled WebContents is foreground).
+  MULTI_TABS,
+};
+
 // Registers startup related prefs in |registry|.
 void RegisterPrefs(PrefRegistrySimple* registry);
 
 // Returns true if any UI other than the browser window has been displayed
 // so far.  Useful to test if UI has been displayed before the first browser
 // window was shown, which would invalidate any surrounding timing metrics.
 bool WasNonBrowserUIDisplayed();
 
 // Call this when displaying UI that might potentially delay startup events.
 //
@@ skipping 37 matching lines @@
 
 // Call this with the time when the first web contents loaded its main frame,
 // only if the first web contents was unimpended in its attempt to do so.
 void RecordFirstWebContentsMainFrameLoad(const base::TimeTicks& ticks);
 
 // Call this with the time when the first web contents had a non-empty paint,
 // only if the first web contents was unimpended in its attempt to do so.
 void RecordFirstWebContentsNonEmptyPaint(const base::TimeTicks& ticks);
 
 // Call this with the time when the first web contents began navigating its main
-// frame.
-void RecordFirstWebContentsMainNavigationStart(const base::TimeTicks& ticks);
+// frame. Adds a suffix to its metrics according to |workload|.
+void RecordFirstWebContentsMainNavigationStart(const base::TimeTicks& ticks,
+                                               WebContentsWorkload workload);
 
 // Call this with the time when the first web contents successfully committed
 // its navigation for the main frame.
 void RecordFirstWebContentsMainNavigationFinished(const base::TimeTicks& ticks);
 
 // Returns the TimeTicks corresponding to main entry as recorded by
 // RecordMainEntryPointTime. Returns a null TimeTicks if a value has not been
 // recorded yet. This method is expected to be called from the UI thread.
 base::TimeTicks MainEntryPointTicks();
 
 }  // namespace startup_metric_utils
 
 #endif  // COMPONENTS_STARTUP_METRIC_UTILS_BROWSER_STARTUP_METRIC_UTILS_H_