Remove unneeded "using" statements and blink prefixes

Source/core/html/HTMLMediaElement.h

Index: Source/core/html/HTMLMediaElement.h
diff --git a/Source/core/html/HTMLMediaElement.h b/Source/core/html/HTMLMediaElement.h
index 6cdc6faf30d5ba317298a5e871fc2c74c89f502e..d45ec851da3101088a86619cc758cd05dd8490b5 100644
--- a/Source/core/html/HTMLMediaElement.h
+++ b/Source/core/html/HTMLMediaElement.h
@@ -41,11 +41,6 @@
 #endif
 
 namespace blink {
-class WebInbandTextTrack;
-class WebLayer;
-}
-
-namespace blink {
 
 #if ENABLE(WEB_AUDIO)
 class AudioSourceProviderClient;
@@ -68,6 +63,8 @@ class TextTrackList;
 class TimeRanges;
 class URLRegistry;
 class VideoTrackList;
+class WebInbandTextTrack;
+class WebLayer;
 
 class CORE_EXPORT HTMLMediaElement : public HTMLElement, public WillBeHeapSupplementable<HTMLMediaElement>, public ActiveDOMObject, private WebMediaPlayerClient {
     DEFINE_WRAPPERTYPEINFO();