| // 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 main_render_frame_id, the |
| // WebContentsTracker tracks changes to the active RenderFrameHost tree during |
| // the lifetime of a WebContents instance. This is used to maintain capture of |
| // the WebContents's video and audio across page transitions such as user |
| // navigations, crashes, iframes, etc.. |
| // |
| // Threading issues: Start(), Stop() and the ChangeCallback must be invoked on |
| // the same thread. This can be any thread, and the decision is locked-in once |
| // WebContentsTracker::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/macros.h" |
| #include "base/memory/ref_counted.h" |
| #include "content/common/content_export.h" |
| #include "content/public/browser/web_contents_observer.h" |
| |
| namespace base { |
| class SingleThreadTaskRunner; |
| } |
| |
| namespace content { |
| |
| class RenderWidgetHostView; |
| |
| class CONTENT_EXPORT WebContentsTracker |
| : public base::RefCountedThreadSafe<WebContentsTracker>, |
| public WebContentsObserver { |
| public: |
| WebContentsTracker(); |
| |
| // Callback to indicate a new RenderWidgetHostView should be targeted for |
| // capture. This is also invoked with false to indicate tracking will not |
| // continue (i.e., the WebContents instance was not found or has been |
| // destroyed). |
| typedef base::Callback<void(bool was_still_tracking)> ChangeCallback; |
| |
| // Start tracking. The last-known |render_process_id| and |
| // |main_render_frame_id| are provided, and |callback| will be run once to |
| // indicate whether tracking successfully started (this may occur during the |
| // invocation of Start(), or in the future). The callback will be invoked on |
| // the same thread calling Start(). |
| virtual void Start(int render_process_id, int main_render_frame_id, |
| const ChangeCallback& callback); |
| |
| // Stop tracking. Once this method returns, the callback is guaranteed not to |
| // be invoked again. |
| virtual void Stop(); |
| |
| // Returns true if this tracker is still able to continue tracking changes. |
| // This must only be called on the UI BrowserThread. |
| bool is_still_tracking() const { return !!web_contents(); } |
| |
| // Current target view. May return nullptr during certain transient periods. |
| // This must only be called on the UI BrowserThread. |
| RenderWidgetHostView* GetTargetView() const; |
| |
| // Set a callback that is run whenever the main frame of the WebContents is |
| // resized. This method must be called on the same thread that calls |
| // Start()/Stop(), and |callback| will be run on that same thread. Calling |
| // the Stop() method guarantees the callback will never be invoked again. |
| void SetResizeChangeCallback(const base::Closure& callback); |
| |
| protected: |
| friend class base::RefCountedThreadSafe<WebContentsTracker>; |
| ~WebContentsTracker() override; |
| |
| private: |
| // Determine the target RenderWidgetHostView and, if different from that last |
| // reported, runs the ChangeCallback on the appropriate thread. If |
| // |force_callback_run| is true, the ChangeCallback is run even if the |
| // RenderWidgetHostView has not changed. |
| void OnPossibleTargetChange(bool force_callback_run); |
| |
| // Called on the thread that Start()/Stop() are called on. Checks whether the |
| // callback is still valid and, if so, runs it. |
| void MaybeDoCallback(bool was_still_tracking); |
| |
| // Called on the thread that Start()/Stop() are called on. Checks whether the |
| // callback is still valid and, if so, runs it to indicate the main frame has |
| // changed in size. |
| void MaybeDoResizeCallback(); |
| |
| // Look-up the current WebContents instance associated with the given |
| // |render_process_id| and |main_render_frame_id| and begin observing it. |
| void StartObservingWebContents(int render_process_id, |
| int main_render_frame_id); |
| |
| // WebContentsObserver overrides: These events indicate that the view of the |
| // main frame may have changed. |
| void RenderFrameCreated(RenderFrameHost* render_frame_host) final; |
| void RenderFrameDeleted(RenderFrameHost* render_frame_host) final; |
| void RenderFrameHostChanged(RenderFrameHost* old_host, |
| RenderFrameHost* new_host) final; |
| |
| // WebContentsObserver override to notify the client that the source size has |
| // changed. |
| void MainFrameWasResized(bool width_changed) final; |
| |
| // WebContentsObserver override to notify the client that the capture target |
| // has been permanently lost. |
| void WebContentsDestroyed() final; |
| |
| // WebContentsObserver overrides to notify the client that the capture target |
| // may have changed due to a separate fullscreen widget shown/destroyed. |
| void DidShowFullscreenWidget() final; |
| void DidDestroyFullscreenWidget() final; |
| |
| // Pointer to the RenderWidgetHostView provided in the last run of |
| // |callback_|. This is used to eliminate duplicate callback runs. |
| RenderWidgetHostView* last_target_view_; |
| |
| // TaskRunner corresponding to the thread that called Start(). |
| scoped_refptr<base::SingleThreadTaskRunner> task_runner_; |
| |
| // Callback to run when the target RenderWidgetHostView has changed. |
| ChangeCallback callback_; |
| |
| // Callback to run when the target RenderWidgetHostView has resized. |
| base::Closure resize_callback_; |
| |
| DISALLOW_COPY_AND_ASSIGN(WebContentsTracker); |
| }; |
| |
| } // namespace content |
| |
| #endif // CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_TRACKER_H_ |