Make IDBTransactionCoordinatorLevelDB cross platform

Make IDBTransactionCoordinatorLevelDB cross platform
https://bugs.webkit.org/show_bug.cgi?id=123124

Enthusiastically reviewed by Tim Horton.

* CMakeLists.txt:
* GNUmakefile.list.am:
* WebCore.xcodeproj/project.pbxproj:

Make more methods pure virtual in the interface:
* Modules/indexeddb/IDBTransactionBackendInterface.h:
* Modules/indexeddb/leveldb/IDBTransactionBackendLevelDB.cpp:
* Modules/indexeddb/leveldb/IDBTransactionBackendLevelDB.h:

Update the name of the class, and use IDBTransactionBackendInterface instead of IDBTransactionBackendLeveDB:
* Modules/indexeddb/IDBTransactionCoordinator.cpp: Renamed from Source/WebCore/Modules/indexeddb/leveldb/IDBTransactionCoordinatorLevelDB.cpp.
(WebCore::IDBTransactionCoordinator::create):
(WebCore::IDBTransactionCoordinator::IDBTransactionCoordinator):
(WebCore::IDBTransactionCoordinator::~IDBTransactionCoordinator):
(WebCore::IDBTransactionCoordinator::didCreateTransaction):
(WebCore::IDBTransactionCoordinator::didStartTransaction):
(WebCore::IDBTransactionCoordinator::didFinishTransaction):
(WebCore::IDBTransactionCoordinator::isActive):
(WebCore::IDBTransactionCoordinator::processStartedTransactions):
(WebCore::doScopesOverlap):
(WebCore::IDBTransactionCoordinator::canRunTransaction):
* Modules/indexeddb/IDBTransactionCoordinator.h: Renamed from Source/WebCore/Modules/indexeddb/leveldb/IDBTransactionCoordinatorLevelDB.h.

Update the name of the class elsewhere:
* Modules/indexeddb/leveldb/IDBDatabaseBackendLevelDB.cpp:
(WebCore::IDBDatabaseBackendLevelDB::IDBDatabaseBackendLevelDB):
* Modules/indexeddb/leveldb/IDBDatabaseBackendLevelDB.h:
(WebCore::IDBDatabaseBackendLevelDB::transactionCoordinator):
* Modules/indexeddb/leveldb/IDBFactoryBackendLevelDB.cpp:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@157766 268f45cc-cd09-0410-ab3c-d52691b4dbfc