Measure the usage of navigator.vibrate in for user gesture & subframe.

third_party/WebKit/Source/modules/vibration/NavigatorVibration.cpp

 /*
  *  Copyright (C) 2012 Samsung Electronics
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Library General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
  *
  *  This library is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  *  Library General Public License for more details.
  *
  *  You should have received a copy of the GNU Library General Public License
  *  along with this library; see the file COPYING.LIB.  If not, write to
  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  *  Boston, MA 02110-1301, USA.
  */
 
 #include "modules/vibration/NavigatorVibration.h"
 
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Navigator.h"
 #include "core/frame/UseCounter.h"

[Michael van Ouwerkerk, 2016/06/28 11:45:52]

Delete this as it is no longer used.

 #include "core/page/Page.h"
 #include "modules/vibration/VibrationController.h"
+#include "platform/Histogram.h"
+#include "platform/UserGestureIndicator.h"
 
 namespace blink {
 
 NavigatorVibration::NavigatorVibration(Navigator& navigator)
     : DOMWindowProperty(navigator.frame())
 {
 }
 
 NavigatorVibration::~NavigatorVibration()
 {
@@ skipping 27 matching lines @@
 // static
 bool NavigatorVibration::vibrate(Navigator& navigator, const VibrationPattern& pattern)
 {
     LocalFrame* frame = navigator.frame();
 
     // There will be no frame if the window has been closed, but a JavaScript
     // reference to |window| or |navigator| was retained in another window.
     if (!frame)
         return false;
 
-    UseCounter::count(frame, UseCounter::NavigatorVibrate);
-    if (!frame->isMainFrame())
-        UseCounter::count(frame, UseCounter::NavigatorVibrateSubFrame);
+    const unsigned userGestureBit = 0x1;

[Michael van Ouwerkerk, 2016/06/28 11:45:53]

I don't find this section very readable, using bit manipulation. Why not have
some conditionals that set the actual enum value directly? You could get rid of
the static_cast as well that way.

+    const unsigned subFrameBit = 0x2;
+    const unsigned crossOriginFrameBit = 0x4;
+    unsigned vibrateParams = 0;
+    if (UserGestureIndicator::processingUserGesture())
+        vibrateParams |= userGestureBit;
+    if (!frame->isMainFrame()) {
+        if (frame->isCrossOrigin())
+            vibrateParams |= crossOriginFrameBit;
+        else
+            vibrateParams |= subFrameBit;
+    }
+    DEFINE_STATIC_LOCAL(EnumerationHistogram, NavigatorVibrateHistogram, ("Vibration.Context", NavigatorVibrationType::EnumMax));
+    NavigatorVibrateHistogram.count(static_cast<NavigatorVibrationType>(vibrateParams));
 
     DCHECK(frame->document());
     DCHECK(frame->page());
 
     if (!frame->page()->isPageVisible())
         return false;
 
     return NavigatorVibration::from(navigator).controller()->vibrate(pattern);
 }
 
@@ skipping 14 matching lines @@
 }
 
 DEFINE_TRACE(NavigatorVibration)
 {
     visitor->trace(m_controller);
     Supplement<Navigator>::trace(visitor);
     DOMWindowProperty::trace(visitor);
 }
 
 } // namespace blink