WebAudio: record whether user gesture was available and provided.

third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.h

Index: third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.h
diff --git a/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.h b/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.h
index 53c158fbf02b32cbf9f524272e9b02c81b760289..6722b8b8fe24c66c766bc540ee5bef9f1a55f798 100644
--- a/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.h
+++ b/third_party/WebKit/Source/modules/webaudio/AbstractAudioContext.h
@@ -261,6 +261,12 @@ public:
     // Get the PeriodicWave for the specified oscillator type.  The table is initialized internally
     // if necessary.
     PeriodicWave* periodicWave(int type);
+
+    // Check whether the AudioContext requires a user gesture and whether the
+    // current stack is processing user gesture and record these information in
+    // a histogram.
+    void recordUserGesture();
+
 protected:
     explicit AbstractAudioContext(Document*);
     AbstractAudioContext(Document*, unsigned numberOfChannels, size_t numberOfFrames, float sampleRate);
@@ -336,6 +342,9 @@ private:
     // excessive number of times.
     bool m_isResolvingResumePromises;
 
+    // Whether a user gesture is required to start this AudioContext.
+    bool m_userGestureRequired;
+
     unsigned m_connectionCount;
 
     // Graph locking.