Add CombinedDesktopMediaList class

chrome/browser/media/desktop_media_list_base.h

 // Copyright 2016 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_MEDIA_DESKTOP_MEDIA_LIST_BASE_H_
 #define CHROME_BROWSER_MEDIA_DESKTOP_MEDIA_LIST_BASE_H_
 
 #include "chrome/browser/media/desktop_media_list.h"
 #include "content/public/browser/desktop_media_id.h"
 
 // Thumbnail size is 100*100 pixels
 static const int kDefaultThumbnailSize = 100;
 
-// Base class for DesktopMedaiList implementations. Implements logic shared
+// Base class for DesktopMediaList implementations. Implements logic shared
 // between implementations. Specifically it's responsible for keeping current
 // list of sources and calling the observer when the list changes.
 class DesktopMediaListBase : public DesktopMediaList {
  public:
   explicit DesktopMediaListBase(base::TimeDelta update_period);
   ~DesktopMediaListBase() override;
 
   // DesktopMediaList interface.
   void SetUpdatePeriod(base::TimeDelta period) override;
   void SetThumbnailSize(const gfx::Size& thumbnail_size) override;
@@ skipping 39 matching lines @@
 
   // The observer passed to StartUpdating().
   DesktopMediaListObserver* observer_ = nullptr;
 
   base::WeakPtrFactory<DesktopMediaListBase> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopMediaListBase);
 };
 
 #endif  // CHROME_BROWSER_MEDIA_DESKTOP_MEDIA_LIST_BASE_H_