Make WebContentsObserver::DidGetUserInteraction fire on TouchStart instead of GestureTapBegin.

content/public/browser/web_contents_observer.h

Index: content/public/browser/web_contents_observer.h
diff --git a/content/public/browser/web_contents_observer.h b/content/public/browser/web_contents_observer.h
index 8f0ca7732f62c0752fb141bfdc702acd0e4f2772..cd8a4a377b222b4701e2f83013708570aa584eac 100644
--- a/content/public/browser/web_contents_observer.h
+++ b/content/public/browser/web_contents_observer.h
@@ -353,7 +353,7 @@ class CONTENT_EXPORT WebContentsObserver : public IPC::Listener,
   // 1) any mouse down event (blink::WebInputEvent::MouseDown);
   // 2) the start of a scroll (blink::WebInputEvent::GestureScrollBegin);
   // 3) any raw key down event (blink::WebInputEvent::RawKeyDown);
-  // 4) any gesture tap event (blink::WebInputEvent::GestureTapDown); and
+  // 4) any touch event (inc. scrolls) (blink::WebInputEvent::TouchStart); and
   // 5) a browser navigation or reload (blink::WebInputEvent::Undefined).
   virtual void DidGetUserInteraction(const blink::WebInputEvent::Type type) {}