Cleanup namespace usage in public/platform/{Web[P-W]*,linux/*}.h

public/platform/WebPermissionCallbacks.h

Index: public/platform/WebPermissionCallbacks.h
diff --git a/public/platform/WebPermissionCallbacks.h b/public/platform/WebPermissionCallbacks.h
index a19a7ac3d2199fa2ea963819a32fd79cdef809c6..59e917291d84658151e7078306b950c310c995a0 100644
--- a/public/platform/WebPermissionCallbacks.h
+++ b/public/platform/WebPermissionCallbacks.h
@@ -7,14 +7,11 @@
 
 #include "WebPrivatePtr.h"
 
-namespace blink {
-class PermissionCallbacks;
-}
-
 namespace WTF { template <typename T> class PassOwnPtr; }
 
 namespace blink {
 
+class PermissionCallbacks;
 class WebPermissionCallbacksPrivate;
 
 class WebPermissionCallbacks {
@@ -32,7 +29,7 @@ public:
     BLINK_PLATFORM_EXPORT void assign(const WebPermissionCallbacks&);
 
 #if INSIDE_BLINK
-    BLINK_PLATFORM_EXPORT WebPermissionCallbacks(const WTF::PassOwnPtr<blink::PermissionCallbacks>&);
+    BLINK_PLATFORM_EXPORT WebPermissionCallbacks(const WTF::PassOwnPtr<PermissionCallbacks>&);
 #endif
 
     BLINK_PLATFORM_EXPORT void doAllow();