Source/WebCore: The IDB backing store get() method shouldn't call IDB callbacks directly

https://bugs.webkit.org/show_bug.cgi?id=127453

Reviewed by Beth Dakin.

* Modules/indexeddb/IDBServerConnection.h:
(WebCore::IDBGetResult::IDBGetResult): Add a new structure to hold all of the
  possible results of a get() call.

* Modules/indexeddb/leveldb/IDBServerConnectionLevelDB.cpp:
(WebCore::IDBServerConnectionLevelDB::get): Don't call IDBCallbacks directly.
  Instead, return the GetResult to the GetOperation which will make IDBCallbacks.
* Modules/indexeddb/leveldb/IDBServerConnectionLevelDB.h:

* Modules/indexeddb/IDBTransactionBackendOperations.cpp:
(WebCore::GetOperation::perform): Get all of the IDBGetResults in the completion callback
  make the appropriate IDBCallback.
* Modules/indexeddb/IDBTransactionBackendOperations.h:

Source/WebKit2: The IDB backing store get() method shouldn't call IDB callbacks directly
https://bugs.webkit.org/show_bug.cgi?id=127453

Reviewed by Beth Dakin.

* WebProcess/Databases/IndexedDB/WebIDBServerConnection.cpp:
(WebKit::WebIDBServerConnection::get):
* WebProcess/Databases/IndexedDB/WebIDBServerConnection.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@162569 268f45cc-cd09-0410-ab3c-d52691b4dbfc