move KeyUsageAllows to more logical place(part1)

public/platform/WebCryptoKey.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 102 matching lines @@
     //   * Returned pointer's lifetime is bound to |this|
     BLINK_PLATFORM_EXPORT WebCryptoKeyHandle* handle() const;
 
     BLINK_PLATFORM_EXPORT WebCryptoKeyType type() const;
     BLINK_PLATFORM_EXPORT bool extractable() const;
     BLINK_PLATFORM_EXPORT const WebCryptoKeyAlgorithm& algorithm() const;
     BLINK_PLATFORM_EXPORT WebCryptoKeyUsageMask usages() const;
 
     BLINK_PLATFORM_EXPORT bool isNull() const;
 
+    BLINK_PLATFORM_EXPORT bool keyUsageAllows(const blink::WebCryptoKeyUsage) const;
+
 private:
     BLINK_PLATFORM_EXPORT void assign(const WebCryptoKey& other);
     BLINK_PLATFORM_EXPORT void reset();
 
     WebPrivatePtr<WebCryptoKeyPrivate> m_private;
 };
 
 // Base class for the embedder to define its own opaque key handle. The lifetime
 // of this object is controlled by WebCryptoKey using reference counting.
 class WebCryptoKeyHandle {
 public:
     virtual ~WebCryptoKeyHandle() { }
 };
 
 } // namespace blink
 
 #endif