WebCrypto: Add interfaces for importKey().

Source/modules/crypto/SubtleCrypto.h

Index: Source/modules/crypto/SubtleCrypto.h
diff --git a/Source/modules/crypto/SubtleCrypto.h b/Source/modules/crypto/SubtleCrypto.h
index 3df45a197d05977e28b5400d8cbc27464cdfb46e..e68422d5b12b684be5e59c0d0e35ea0a708ca4c6 100644
--- a/Source/modules/crypto/SubtleCrypto.h
+++ b/Source/modules/crypto/SubtleCrypto.h
@@ -31,6 +31,7 @@
 #ifndef SubtleCrypto_h
 #define SubtleCrypto_h
 
+#include "bindings/v8/ScriptObject.h"
 #include "bindings/v8/ScriptWrappable.h"
 #include "wtf/Forward.h"
 #include "wtf/PassRefPtr.h"
@@ -54,6 +55,8 @@ public:
     PassRefPtr<CryptoOperation> verifySignature(const Dictionary&, ExceptionCode&);
     PassRefPtr<CryptoOperation> digest(const Dictionary&, ExceptionCode&);
 
+    ScriptObject importKey(const String&, ArrayBufferView*, const Dictionary&, bool extractable, const Vector<String>& keyUsages, ExceptionCode&);
+
 private:
     SubtleCrypto();
 };