Notify WebContentsObservers of user interactions.

content/public/browser/web_contents_observer.h

 // Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_
 
 #include "base/process/kill.h"
 #include "base/process/process_handle.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/common/frame_navigate_params.h"
 #include "content/public/common/security_style.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/base/page_transition_types.h"
 #include "ui/base/window_open_disposition.h"
 
 namespace content {
 
 class NavigationEntry;
 class NavigationHandle;
 class RenderFrameHost;
 class RenderViewHost;
@@ skipping 280 matching lines @@
   // This method is invoked when the renderer process has completed its first
   // paint after a non-empty layout.
   virtual void DidFirstVisuallyNonEmptyPaint() {}
 
   // When WebContents::Stop() is called, the WebContents stops loading and then
   // invokes this method. If there are ongoing navigations, their respective
   // failure methods will also be invoked.
   virtual void NavigationStopped() {}
 
   // This indicates that the next navigation was triggered by a user gesture.
+  // TODO(dominickn): remove this method in favor of DidStartUserInteraction,
+  // with the appropriate filtering by input event type.
   virtual void DidGetUserGesture() {}
 
+  // Called when there has been direct user interaction with the web contents.
+  // Direct user input includes 1) any mouse down event; 2) any mouse wheel
+  // event; 3) any raw key down event; and 4) any gesture tap event.
+  virtual void DidStartUserInteraction(const blink::WebInputEvent::Type type) {}

[nasko, 2015/10/26 17:18:44]

Any method that has a Start in its name should have a corresponding Stop method.
I don't see one. Why is that?

[dominickn, 2015/10/27 07:03:57]

The naming was a reviewer suggestion. I've changed it to remove the Start and
the implication that there should be a stop.

+
   // This method is invoked when a RenderViewHost of this WebContents was
   // configured to ignore UI events, and an UI event took place.
   virtual void DidGetIgnoredUIEvent() {}
 
   // These methods are invoked every time the WebContents changes visibility.
   virtual void WasShown() {}
   virtual void WasHidden() {}
 
   // Invoked when the main frame changes size.
   virtual void MainFrameWasResized(bool width_changed) {}
@@ skipping 127 matching lines @@
   void ResetWebContents();
 
   WebContentsImpl* web_contents_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_