[webcrypto] Implement structured clone of keys (blink-side).

public/platform/WebCryptoAlgorithm.h

Index: public/platform/WebCryptoAlgorithm.h
diff --git a/public/platform/WebCryptoAlgorithm.h b/public/platform/WebCryptoAlgorithm.h
index 68a8640ceb544c866ffbf1b832904ab2842cf3c9..d64fc682173059e0174d0e84d2f9062d300cfcfd 100644
--- a/public/platform/WebCryptoAlgorithm.h
+++ b/public/platform/WebCryptoAlgorithm.h
@@ -54,7 +54,7 @@ enum WebCryptoAlgorithmId {
     WebCryptoAlgorithmIdAesCtr,
     WebCryptoAlgorithmIdAesKw,
 #if INSIDE_BLINK
-    NumberOfWebCryptoAlgorithmId,
+    WebCryptoAlgorithmIdLast = WebCryptoAlgorithmIdAesKw,
 #endif
 };
 
@@ -131,6 +131,9 @@ public:
     BLINK_PLATFORM_EXPORT const WebCryptoRsaHashedImportParams* rsaHashedImportParams() const;
     BLINK_PLATFORM_EXPORT const WebCryptoRsaHashedKeyGenParams* rsaHashedKeyGenParams() const;
 
+    // Returns true if the provided algorithm ID is for a hash (in other words, SHA-*)
+    BLINK_PLATFORM_EXPORT static bool isHash(WebCryptoAlgorithmId);
+
 private:
     BLINK_PLATFORM_EXPORT void assign(const WebCryptoAlgorithm& other);
     BLINK_PLATFORM_EXPORT void reset();