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

public/platform/WebConvertableToTraceFormat.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WebConvertableToTraceFormat_h
 #define WebConvertableToTraceFormat_h
 
 #include "WebPrivatePtr.h"
 #include "WebString.h"
 
 namespace blink {
+
 namespace TraceEvent {
 class ConvertableToTraceFormat;
 }
-}
-
-namespace blink {
 
 class WebConvertableToTraceFormat {
 public:
     WebConvertableToTraceFormat() { }
 #if INSIDE_BLINK
-    WebConvertableToTraceFormat(blink::TraceEvent::ConvertableToTraceFormat*);
+    WebConvertableToTraceFormat(TraceEvent::ConvertableToTraceFormat*);
 #endif
     ~WebConvertableToTraceFormat() { reset(); }
 
     BLINK_PLATFORM_EXPORT WebString asTraceFormat() const;
     BLINK_PLATFORM_EXPORT void assign(const WebConvertableToTraceFormat&);
     BLINK_PLATFORM_EXPORT void reset();
 
     WebConvertableToTraceFormat(const WebConvertableToTraceFormat& r) { assign(r); }
     WebConvertableToTraceFormat& operator=(const WebConvertableToTraceFormat& r)
     {
         assign(r);
         return *this;
     }
 
 private:
-    WebPrivatePtr<blink::TraceEvent::ConvertableToTraceFormat> m_private;
+    WebPrivatePtr<TraceEvent::ConvertableToTraceFormat> m_private;
 };
 
 } // namespace blink
 
 #endif