Cleanup namespace usage in public/web/Web[A-M]*.h.

public/web/WebMediaDevicesRequest.h

Index: public/web/WebMediaDevicesRequest.h
diff --git a/public/web/WebMediaDevicesRequest.h b/public/web/WebMediaDevicesRequest.h
index 7dc5781389fb45e9b0f56c37708cb851a4b2ae65..a0126e712346154529337239a9ba3a666b64f019 100644
--- a/public/web/WebMediaDevicesRequest.h
+++ b/public/web/WebMediaDevicesRequest.h
@@ -32,10 +32,8 @@
 #include "public/platform/WebString.h"
 
 namespace blink {
-class MediaDevicesRequest;
-}
 
-namespace blink {
+class MediaDevicesRequest;
 class WebDocument;
 class WebMediaDeviceInfo;
 template <typename T> class WebVector;
@@ -63,12 +61,12 @@ public:
     BLINK_EXPORT void requestSucceeded(WebVector<WebMediaDeviceInfo>);
 
 #if BLINK_IMPLEMENTATION
-    WebMediaDevicesRequest(blink::MediaDevicesRequest*);
-    operator blink::MediaDevicesRequest*() const;
+    WebMediaDevicesRequest(MediaDevicesRequest*);
+    operator MediaDevicesRequest*() const;
 #endif
 
 private:
-    WebPrivatePtr<blink::MediaDevicesRequest> m_private;
+    WebPrivatePtr<MediaDevicesRequest> m_private;
 };
 
 inline bool operator==(const WebMediaDevicesRequest& a, const WebMediaDevicesRequest& b)