[webcrypto] Add key usage for 'deriveBits'

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 32 matching lines @@
 };
 
 enum WebCryptoKeyUsage {
     WebCryptoKeyUsageEncrypt = 1 << 0,
     WebCryptoKeyUsageDecrypt = 1 << 1,
     WebCryptoKeyUsageSign = 1 << 2,
     WebCryptoKeyUsageVerify = 1 << 3,
     WebCryptoKeyUsageDeriveKey = 1 << 4,
     WebCryptoKeyUsageWrapKey = 1 << 5,
     WebCryptoKeyUsageUnwrapKey = 1 << 6,
+    WebCryptoKeyUsageDeriveBits = 1 << 7,
 #if INSIDE_BLINK
     EndOfWebCryptoKeyUsage,
 #endif
 };
 
 // A bitfield of WebCryptoKeyUsage
 typedef int WebCryptoKeyUsageMask;
 
 enum WebCryptoKeyFormat {
     WebCryptoKeyFormatRaw,
@@ skipping 65 matching lines @@
 // 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