Introduce KeepAliveWhilePending to ScriptPromiseResolverWithContext.

Source/platform/CryptoResult.h

Index: Source/platform/CryptoResult.h
diff --git a/Source/platform/CryptoResult.h b/Source/platform/CryptoResult.h
index af8032bc57997e4bd35febe1d797d841d1682a14..6a0fa4c94569ce78fb1c413f5d8296ecf04f8ebd 100644
--- a/Source/platform/CryptoResult.h
+++ b/Source/platform/CryptoResult.h
@@ -37,15 +37,19 @@
 namespace WebCore {
 
 // Receives notification of completion of the crypto operation.
-class CryptoResult : public ThreadSafeRefCounted<CryptoResult> {
+class CryptoResultBase {
 public:
-    virtual ~CryptoResult() { }
-
+    virtual ~CryptoResultBase() { }
     virtual void completeWithError(blink::WebCryptoErrorType, const blink::WebString&) = 0;
     virtual void completeWithBuffer(const blink::WebArrayBuffer&) = 0;
     virtual void completeWithBoolean(bool) = 0;
     virtual void completeWithKey(const blink::WebCryptoKey&) = 0;
     virtual void completeWithKeyPair(const blink::WebCryptoKey& publicKey, const blink::WebCryptoKey& privateKey) = 0;
+};
+
+class CryptoResult : public ThreadSafeRefCounted<CryptoResult>, public CryptoResultBase {
+public:
+    virtual ~CryptoResult() { }
 
     blink::WebCryptoResult result()
     {