Eliminate MediaPlayer & MediaPlayerClient abstractions

Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'Clock.cpp',
@@ skipping 272 matching lines @@
       'exported/WebEncryptedMediaKeyInformation.cpp',
       'exported/WebEncryptedMediaRequest.cpp',
       'exported/WebFederatedCredential.cpp',
       'exported/WebFileSystemCallbacks.cpp',
       'exported/WebFilterKeyframe.cpp',
       'exported/WebHTTPBody.cpp',
       'exported/WebHTTPLoadInfo.cpp',
       'exported/WebImageSkia.cpp',
       'exported/WebMediaConstraints.cpp',
       'exported/WebMediaDeviceInfo.cpp',
+      'exported/WebMediaPlayerClient.cpp',
+      'exported/WebMediaPlayerEncryptedMediaClient.cpp',
       'exported/WebMediaStream.cpp',
       'exported/WebMediaStreamSource.cpp',
       'exported/WebMediaStreamTrack.cpp',
       'exported/WebMediaStreamTrackSourcesRequest.cpp',
       'exported/WebMemoryAllocatorDump.cpp',
       'exported/WebMemoryDumpProvider.cpp',
       'exported/WebMessagePortChannelClient.cpp',
       'exported/WebPasswordCredential.cpp',
       'exported/WebPrerender.cpp',
       'exported/WebPrerenderingSupport.cpp',
@@ skipping 332 matching lines @@
       'graphics/filters/SpotLightSource.cpp',
       'graphics/filters/SpotLightSource.h',
       'graphics/gpu/AcceleratedImageBufferSurface.cpp',
       'graphics/gpu/AcceleratedImageBufferSurface.h',
       'graphics/gpu/DrawingBuffer.cpp',
       'graphics/gpu/DrawingBuffer.h',
       'graphics/gpu/Extensions3DUtil.cpp',
       'graphics/gpu/Extensions3DUtil.h',
       'graphics/gpu/WebGLImageConversion.cpp',
       'graphics/gpu/WebGLImageConversion.h',
-      'graphics/media/MediaPlayer.cpp',
-      'graphics/media/MediaPlayer.h',
       'graphics/paint/CachedDisplayItem.h',
       'graphics/paint/ClipDisplayItem.cpp',
       'graphics/paint/ClipDisplayItem.h',
       'graphics/paint/ClipPathDisplayItem.cpp',
       'graphics/paint/ClipPathDisplayItem.h',
       'graphics/paint/ClipPathRecorder.cpp',
       'graphics/paint/ClipPathRecorder.h',
       'graphics/paint/ClipRecorder.cpp',
       'graphics/paint/ClipRecorder.h',
       'graphics/paint/DisplayItem.cpp',
@@ skipping 386 matching lines @@
       ['os_posix==1 and OS!="mac"',
         {
           'platform_test_files': [
             'text/LocaleICUTest.cpp',
           ],
         }
       ],
     ],
   },
 }