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

public/platform/WebContentDecryptionModuleResult.h

Index: public/platform/WebContentDecryptionModuleResult.h
diff --git a/public/platform/WebContentDecryptionModuleResult.h b/public/platform/WebContentDecryptionModuleResult.h
index 4cd224eb2b2f4ba73e0c548878bfa9bee282e927..11f5a111b2fb243e44b251d07eeb907505184b0b 100644
--- a/public/platform/WebContentDecryptionModuleResult.h
+++ b/public/platform/WebContentDecryptionModuleResult.h
@@ -10,11 +10,8 @@
 #include "WebPrivatePtr.h"
 
 namespace blink {
-class ContentDecryptionModuleResult;
-}
-
-namespace blink {
 
+class ContentDecryptionModuleResult;
 class WebString;
 
 class WebContentDecryptionModuleResult {
@@ -58,14 +55,14 @@ public:
     BLINK_PLATFORM_EXPORT void completeWithError(WebContentDecryptionModuleException, unsigned long systemCode, const WebString& message);
 
 #if INSIDE_BLINK
-    BLINK_PLATFORM_EXPORT explicit WebContentDecryptionModuleResult(blink::ContentDecryptionModuleResult*);
+    BLINK_PLATFORM_EXPORT explicit WebContentDecryptionModuleResult(ContentDecryptionModuleResult*);
 #endif
 
 private:
     BLINK_PLATFORM_EXPORT void reset();
     BLINK_PLATFORM_EXPORT void assign(const WebContentDecryptionModuleResult&);
 
-    WebPrivatePtr<blink::ContentDecryptionModuleResult> m_impl;
+    WebPrivatePtr<ContentDecryptionModuleResult> m_impl;
 };
 
 } // namespace blink