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

public/web/WebMIDIPermissionRequest.h

Index: public/web/WebMIDIPermissionRequest.h
diff --git a/public/web/WebMIDIPermissionRequest.h b/public/web/WebMIDIPermissionRequest.h
index 7d37cc86b3d7591a58d334a935ec68e8a7e4afb3..87cafd6919e1798dc3c1b17827430d25decd57da 100644
--- a/public/web/WebMIDIPermissionRequest.h
+++ b/public/web/WebMIDIPermissionRequest.h
@@ -34,11 +34,8 @@
 #include "../platform/WebCommon.h"
 
 namespace blink {
-class MIDIAccessInitializer;
-}
-
-namespace blink {
 
+class MIDIAccessInitializer;
 class WebSecurityOrigin;
 
 // WebMIDIPermissionRequest encapsulates a WebCore MIDIAccessInitializer
@@ -56,13 +53,13 @@ public:
     BLINK_EXPORT bool equals(const WebMIDIPermissionRequest&) const;
 
 #if BLINK_IMPLEMENTATION
-    explicit WebMIDIPermissionRequest(blink::MIDIAccessInitializer*);
+    explicit WebMIDIPermissionRequest(MIDIAccessInitializer*);
 
-    blink::MIDIAccessInitializer* midiAccessInitializer() const { return m_initializer; }
+    MIDIAccessInitializer* midiAccessInitializer() const { return m_initializer; }
 #endif
 
 private:
-    blink::MIDIAccessInitializer* m_initializer;
+    MIDIAccessInitializer* m_initializer;
 };
 
 inline bool operator==(const WebMIDIPermissionRequest& a, const WebMIDIPermissionRequest& b)