[webcrypto] Match the error handling defined by the spec.

Source/core/platform/chromium/support/WebCrypto.cpp

Index: Source/core/platform/chromium/support/WebCrypto.cpp
diff --git a/Source/core/platform/chromium/support/WebCrypto.cpp b/Source/core/platform/chromium/support/WebCrypto.cpp
index 3fd68afd82af45ac5795e7ff700004b077e65f99..5800e41e570f036de6548754f2dc8da1679ff450 100644
--- a/Source/core/platform/chromium/support/WebCrypto.cpp
+++ b/Source/core/platform/chromium/support/WebCrypto.cpp
@@ -43,6 +43,15 @@ void WebCryptoResult::completeWithError()
     reset();
 }
 
+void WebCryptoResult::completeWithError(const WebString& errorDetails)
+{
+    // FIXME: The error details are being temporarily discarded. Once the
+    // Chromium side has been updated to emit error details, this should be
+    // enabled and the layouttests rebaselined.
+    m_impl->completeWithError(/*errorDetails*/);
+    reset();
+}
+
 void WebCryptoResult::completeWithBuffer(const WebArrayBuffer& buffer)
 {
     RELEASE_ASSERT(!buffer.isNull());