Add IDL and initial Blink API for Background Sync

Source/modules/background_sync/SyncError.cpp

-// Copyright 2014 The Chromium Authors. All rights reserved.
+// Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
-#include "modules/push_messaging/PushError.h"
+#include "modules/background_sync/SyncError.h"
 
 #include "core/dom/ExceptionCode.h"
 #include "wtf/OwnPtr.h"
 
 namespace blink {
 
-PassRefPtrWillBeRawPtr<DOMException> PushError::take(ScriptPromiseResolver*, WebType* webErrorRaw)
+PassRefPtrWillBeRawPtr<DOMException> SyncError::take(ScriptPromiseResolver*, WebType* webErrorRaw)
 {
     OwnPtr<WebType> webError = adoptPtr(webErrorRaw);
     switch (webError->errorType) {
-    case WebPushError::ErrorTypeAbort:
+    case WebSyncError::ErrorTypeAbort:
         return DOMException::create(AbortError, webError->message);
-    case WebPushError::ErrorTypeNetwork:
-        return DOMException::create(NetworkError, webError->message);
-    case WebPushError::ErrorTypeNotFound:
+    case WebSyncError::ErrorTypeNoPermission:
+        return DOMException::create(QuotaExceededError, webError->message);

[jkarlin, 2015/02/27 20:08:12]

Eventually we'll be able to use PermissionDeniedError, but since that doesn't
exist...

QuotaExceededError isn't quite right, the string for that is "An attempt was
made to add something to storage that exceeded the quota."

How about InvalidAccessError? It's string is: "A parameter or an operation was
not supported by the underlying object."

[iclelland, 2015/03/02 03:51:10]

Done.

+    case WebSyncError::ErrorTypeNotFound:
         return DOMException::create(NotFoundError, webError->message);
-    case WebPushError::ErrorTypeUnknown:
+    case WebSyncError::ErrorTypeUnknown:
         return DOMException::create(UnknownError, webError->message);
     }
     ASSERT_NOT_REACHED();
     return DOMException::create(UnknownError);
 }
 
-void PushError::dispose(WebType* webErrorRaw)
+void SyncError::dispose(WebType* webErrorRaw)
 {
     delete webErrorRaw;
 }
 
 } // namespace blink