| // Copyright (c) 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. |
| // |
| // Given a starting render_process_id and render_view_id, the WebContentsTracker |
| // tracks RenderViewHost instance swapping during the lifetime of a WebContents |
| // instance. This is used when mirroring tab video and audio so that user |
| // navigations, crashes, etc., during a tab's lifetime allow the capturing code |
| // to remain active on the current/latest RenderView. |
| // |
| // Threading issues: Start(), Stop() and the ChangeCallback are invoked on the |
| // same thread. This can be any thread, and the decision is locked-in by |
| // WebContentsTracker when Start() is called. |
| |
| #ifndef CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_TRACKER_H_ |
| #define CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_TRACKER_H_ |
| |
| #include "base/callback.h" |
| #include "base/memory/ref_counted.h" |
| #include "content/common/content_export.h" |
| #include "content/public/browser/web_contents_observer.h" |
| |
| namespace base { |
| class MessageLoopProxy; |
| } |
| |
| namespace content { |
| |
| class CONTENT_EXPORT WebContentsTracker |
| : public base::RefCountedThreadSafe<WebContentsTracker>, |
| public WebContentsObserver { |
| public: |
| WebContentsTracker(); |
| |
| // Callback for whenever the target is swapped. The callback is also invoked |
| // with both arguments set to MSG_ROUTING_NONE to indicate tracking will not |
| // continue (i.e., the WebContents instance was not found or has been |
| // destroyed). |
| typedef base::Callback<void(int render_process_id, int render_view_id)> |
| ChangeCallback; |
| |
| // Start tracking. The last-known |render_process_id| and |render_view_id| |
| // are provided, and the given callback is invoked asynchronously one or more |
| // times. The callback will be invoked on the same thread calling Start(). |
| virtual void Start(int render_process_id, int render_view_id, |
| const ChangeCallback& callback); |
| |
| // Stop tracking. Once this method returns, the callback is guaranteed not to |
| // be invoked again. |
| virtual void Stop(); |
| |
| protected: |
| friend class base::RefCountedThreadSafe<WebContentsTracker>; |
| virtual ~WebContentsTracker(); |
| |
| private: |
| // Reads the render_process_id/render_view_id from the current WebContents |
| // instance and then invokes the callback. |
| void OnWebContentsChangeEvent(); |
| |
| // Called on the thread that Start()/Stop() are called on, check whether the |
| // callback is still valid and, if so, invoke it. |
| void MaybeDoCallback(int render_process_id, int render_view_id); |
| |
| // Look-up the current WebContents instance associated with the given |
| // |render_process_id| and |render_view_id| and begin observing it. |
| void LookUpAndObserveWebContents(int render_process_id, |
| int render_view_id); |
| |
| // WebContentsObserver overrides to react to events of interest. |
| virtual void RenderViewReady() OVERRIDE; |
| virtual void AboutToNavigateRenderView(RenderViewHost* render_view_host) |
| OVERRIDE; |
| virtual void DidNavigateMainFrame(const LoadCommittedDetails& details, |
| const FrameNavigateParams& params) OVERRIDE; |
| virtual void WebContentsDestroyed() OVERRIDE; |
| |
| scoped_refptr<base::MessageLoopProxy> message_loop_; |
| ChangeCallback callback_; |
| |
| DISALLOW_COPY_AND_ASSIGN(WebContentsTracker); |
| }; |
| |
| } // namespace content |
| |
| #endif // CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_TRACKER_H_ |