Implement Chrome Extension TabCapture API

chrome/browser/extensions/api/tab_capture/tab_capture_registry.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 CHROME_BROWSER_EXTENSIONS_API_TAB_CAPTURE_TAB_CAPTURE_REGISTRY_H_
+#define CHROME_BROWSER_EXTENSIONS_API_TAB_CAPTURE_TAB_CAPTURE_REGISTRY_H_
+
+#include <map>
+
+#include "chrome/browser/media/media_internals.h"
+#include "chrome/browser/media/media_internals_observer.h"
+#include "chrome/browser/profiles/profile_keyed_service.h"
+#include "chrome/common/extensions/api/tab_capture.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/media_request_state.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/common/media_stream_request.h"
+
+class Profile;
+
+namespace extensions {
+
+namespace tab_capture = extensions::api::tab_capture;
+
+class TabCaptureRegistry : public ProfileKeyedService,
+                           public content::NotificationObserver {
+ public:
+  struct TabCaptureRequest {
+    std::string extension_id;
+    int tab_id;
+    tab_capture::TabCaptureState status;
+
+    TabCaptureRequest() {}
+    TabCaptureRequest(std::string extension_id, int tab_id,
+                      tab_capture::TabCaptureState status)
+        : extension_id(extension_id), tab_id(tab_id), status(status) {}
+  };
+  typedef std::vector<TabCaptureRequest> CaptureRequestList;
+
+  explicit TabCaptureRegistry(Profile* profile);
+
+  const CaptureRequestList GetCapturedTabs(const std::string& extension_id);
+  bool AddRequest(const std::string& key, const TabCaptureRequest& request);
+  bool VerifyRequest(const std::string& key);
+
+ private:
+  // Maps device_id to information about the media stream request. This is
+  // expected to be small since maintaining a media stream is expensive.
+  typedef std::map<std::string, TabCaptureRequest> DeviceCaptureRequestMap;
+
+  class MediaObserverProxy : public MediaInternalsObserver,
+                             public base::RefCountedThreadSafe<
+                                 MediaObserverProxy> {
+   public:
+    MediaObserverProxy() : handler_(NULL) {}
+    void Attach(TabCaptureRegistry* handler);
+    void Detach();
+
+   private:
+    friend class base::RefCountedThreadSafe<MediaObserverProxy>;
+    virtual ~MediaObserverProxy() {}
+
+    // MediaInternalsObserver.
+    virtual void OnRequestUpdate(
+        const content::MediaStreamDevice& device,
+        const content::MediaRequestState state) OVERRIDE;
+
+    void RegisterAsMediaObserverOnIOThread(bool unregister);
+    void UpdateOnUIThread(
+        const content::MediaStreamDevice& device,
+        const content::MediaRequestState new_state);
+
+    TabCaptureRegistry* handler_;
+  };
+
+  virtual ~TabCaptureRegistry();
+
+  void HandleRequestUpdateOnUIThread(
+      const content::MediaStreamDevice& device,
+      const content::MediaRequestState state);
+
+  // content::NotificationObserver implementation.
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  scoped_refptr<MediaObserverProxy> proxy_;
+  content::NotificationRegistrar registrar_;
+  Profile* const profile_;
+  DeviceCaptureRequestMap requests_;
+
+  DISALLOW_COPY_AND_ASSIGN(TabCaptureRegistry);
+};
+
+}  // namespace extension
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_TAB_CAPTURE_TAB_CAPTURE_REGISTRY_H_