Clean up on media_stream_center.h inclusions

There are some trailing includes, and also some forward declarations
that can be removed.

Drive by CL.

BUG=704136
R=guidou@chromium.org

Change-Id: I2cf0d2e9fcc0e273d759ba870718f87a5359e405
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1704719
Auto-Submit: Antonio Gomes <tonikitoo@igalia.com>
Commit-Queue: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Cr-Commit-Position: refs/heads/master@{#678273}

content/renderer/media/stream/media_stream_center.cc

@@ -12,7 +12,6 @@
 #include "base/logging.h"
 #include "content/renderer/media/stream/processed_local_audio_source.h"
 #include "media/base/sample_format.h"
-#include "third_party/blink/public/platform/modules/mediastream/media_stream_audio_track.h"
 #include "third_party/blink/public/platform/modules/mediastream/web_platform_media_stream_source.h"
 #include "third_party/blink/public/platform/modules/mediastream/webaudio_media_stream_source.h"
 #include "third_party/blink/public/platform/web_media_stream_source.h"
@@ -21,10 +20,6 @@
 #include "third_party/blink/public/web/modules/mediastream/media_stream_video_source.h"
 #include "third_party/blink/public/web/modules/mediastream/media_stream_video_track.h"
 #include "third_party/blink/public/web/modules/mediastream/webaudio_media_stream_audio_sink.h"
-#include "third_party/blink/public/web/web_frame.h"
-
-using blink::WebFrame;
-using blink::WebView;
 
 namespace content {
 

third_party/blink/renderer/modules/mediastream/media_stream.cc

@@ -32,7 +32,6 @@
 #include "third_party/blink/renderer/platform/bindings/exception_state.h"
 #include "third_party/blink/renderer/platform/bindings/script_state.h"
 #include "third_party/blink/renderer/platform/heap/heap.h"
-#include "third_party/blink/renderer/platform/mediastream/media_stream_center.h"
 #include "third_party/blink/renderer/platform/mediastream/media_stream_source.h"
 
 namespace blink {

third_party/blink/renderer/modules/mediastream/user_media_request.cc

@@ -49,7 +49,6 @@
 #include "third_party/blink/renderer/modules/mediastream/user_media_controller.h"
 #include "third_party/blink/renderer/platform/bindings/exception_state.h"
 #include "third_party/blink/renderer/platform/heap/heap.h"
-#include "third_party/blink/renderer/platform/mediastream/media_stream_center.h"
 #include "third_party/blink/renderer/platform/mediastream/media_stream_descriptor.h"
 #include "third_party/blink/renderer/platform/runtime_enabled_features.h"