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

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

Previously the implementation was throwing exceptions for certain errors which the spec says to return a Promise and reject it with "null". [1]

The mechanism described by the spec does not provide for communicating any error details to the developer, since the Promise is rejected with "null".

In order to demystify these errors for developers, this change additionally logs error details to the dev tools console.

The specific errors which were previously throwing an exception and are now rejecting with null + logging to console are:

 * Key is not extractable
 * Key's algorithm doesn't match that of operation
 * Key's usage does not permit the requested operation
 * Any failure in parsing the AlgorithmIdentifier dictionary (with the exception of getting the "name" attribute).

One existing exception was changed:

 * When the AlgorithmIdentifier is either missing a "name" attribute, or the "name" attribute is not a string throw a NotSupportedError - before a TypeError would be thrown.

Lastly, this change allows the embedder to provide error details when failing an operation.

[1] https://dvcs.w3.org/hg/webcrypto-api/raw-file/tip/spec/Overview.html

BUG=245025
BUG=331665
R=abarth@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=165513

[eroman, 2014-01-17 23:05:01]

This builds off of https://codereview.chromium.org/133253002/

abarth: Please review

rsleevi: Please confirm my interpretation of the webcrypto spec mentioned in CL
description.

[abarth-chromium, 2014-01-18 09:05:56]

LGTM assuming rsleevi is happy.

[commit-bot: I haz the power, 2014-01-21 19:44:24]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eroman@chromium.org/141413003/60026

[commit-bot: I haz the power, 2014-01-21 19:44:33]

Failed to apply patch for Source/modules/crypto/CryptoResultImpl.cpp:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  patching file Source/modules/crypto/CryptoResultImpl.cpp
  Hunk #1 FAILED at 45.
  Hunk #2 FAILED at 55.
  2 out of 2 hunks FAILED -- saving rejects to file
Source/modules/crypto/CryptoResultImpl.cpp.rej

Patch:       Source/modules/crypto/CryptoResultImpl.cpp
Index: Source/modules/crypto/CryptoResultImpl.cpp
diff --git a/Source/modules/crypto/CryptoResultImpl.cpp
b/Source/modules/crypto/CryptoResultImpl.cpp
index
cffb519e3f35e01e75dc70b83d138f47c8f74399..ce80306b63d3970a453c414a65d0a1b5c12d7a0a
100644
--- a/Source/modules/crypto/CryptoResultImpl.cpp
+++ b/Source/modules/crypto/CryptoResultImpl.cpp
@@ -45,9 +45,6 @@ namespace WebCore {
 
 CryptoResultImpl::~CryptoResultImpl()
 {
-    ASSERT(m_finished);
-    ASSERT(!m_promiseResolver.get());
-    ASSERT(!m_requestState.isValid());
 }
 
 PassRefPtr<CryptoResultImpl> CryptoResultImpl::create(ScriptPromise promise)
@@ -55,16 +52,23 @@ PassRefPtr<CryptoResultImpl>
CryptoResultImpl::create(ScriptPromise promise)
     return adoptRef(new CryptoResultImpl(activeExecutionContext(), promise));
 }
 
-void CryptoResultImpl::completeWithError()
+void CryptoResultImpl::completeWithError(const blink::WebString& errorDetails)
 {
     ASSERT(!m_finished);
 
     if (canCompletePromise()) {
         DOMRequestState::Scope scope(m_requestState);
+        if (!errorDetails.isEmpty()) {
+            // FIXME: Include the line number which started the crypto
operation.
+            executionContext()->addConsoleMessage(JSMessageSource,
ErrorMessageLevel, errorDetails);
+        }
         m_promiseResolver->reject(ScriptValue::createNull());
     }
+}
 
-    finish();
+void CryptoResultImpl::completeWithError()
+{
+    completeWithError(blink::WebString());
 }
 
 void CryptoResultImpl::completeWithBuffer(const blink::WebArrayBuffer& buffer)

[commit-bot: I haz the power, 2014-01-22 03:27:05]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eroman@chromium.org/141413003/150001

[commit-bot: I haz the power, 2014-01-22 05:58:56]

Retried try job too often on linux_blink_rel for step(s) webkit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_blin...

[eroman, 2014-01-22 06:11:17]

Committed patchset #2 manually as r165513 (presubmit successful).