IndexedDB: Various C++11isms and cleanup

Source/modules/indexeddb/IDBTransaction.cpp

Index: Source/modules/indexeddb/IDBTransaction.cpp
diff --git a/Source/modules/indexeddb/IDBTransaction.cpp b/Source/modules/indexeddb/IDBTransaction.cpp
index f28e2391f9cd793f6d654a8f100bc45b4a282d64..b6b5e5b369c7e92f10fd90027aa73d5eb7a73c55 100644
--- a/Source/modules/indexeddb/IDBTransaction.cpp
+++ b/Source/modules/indexeddb/IDBTransaction.cpp
@@ -90,9 +90,6 @@ IDBTransaction::IDBTransaction(ScriptState* scriptState, int64_t id, const HashS
     , m_objectStoreNames(objectStoreNames)
     , m_openDBRequest(openDBRequest)
     , m_mode(mode)
-    , m_state(Active)
-    , m_hasPendingActivity(true)
-    , m_contextStopped(false)
     , m_previousMetadata(previousMetadata)
 {
     if (mode == WebIDBTransactionModeVersionChange) {
@@ -212,11 +209,9 @@ void IDBTransaction::abort(ExceptionState& exceptionState)
     if (m_contextStopped)
         return;
 
-    while (!m_requestList.isEmpty()) {
-        IDBRequest* request = *m_requestList.begin();
-        m_requestList.remove(request);
+    for (IDBRequest* request : m_requestList)

[cmumford, 2015/09/03 23:21:03]

I seem to remember that aborting one request can sometimes abort (or maybe
enqueue) another. Are you sure this is safe?

[jsbell, 2015/09/03 23:29:54]

Looking at what IDBRequest::abort() does, it should be safe since there are no
synchronous side effects. It can enqueue events but they are dispatched
asynchronously.

I had similar reservations, thinking about changing destruction timing, but now
that everything is GC'd the destruction all happens later anyway.

         request->abort();
-    }
+    m_requestList.clear();
 
     if (backendDB())
         backendDB()->abort(m_id);
@@ -251,17 +246,16 @@ void IDBTransaction::onAbort(DOMError* error)
 
         // Abort was not triggered by front-end, so outstanding requests must
         // be aborted now.
-        while (!m_requestList.isEmpty()) {
-            IDBRequest* request = *m_requestList.begin();
-            m_requestList.remove(request);
+        for (IDBRequest* request : m_requestList)
             request->abort();
-        }
+        m_requestList.clear();
+
         m_state = Finishing;
     }
 
     if (isVersionChange()) {
-        for (IDBObjectStoreMetadataMap::iterator it = m_objectStoreCleanupMap.begin(); it != m_objectStoreCleanupMap.end(); ++it)
-            it->key->setMetadata(it->value);
+        for (auto& it : m_objectStoreCleanupMap)
+            it.key->setMetadata(it.value);
         m_database->setMetadata(m_previousMetadata);
         m_database->close();
     }
@@ -364,11 +358,11 @@ bool IDBTransaction::dispatchEventInternal(PassRefPtrWillBeRawPtr<Event> event)
     m_state = Finished;
 
     // Break reference cycles.
-    for (IDBObjectStoreMap::iterator it = m_objectStoreMap.begin(); it != m_objectStoreMap.end(); ++it)
-        it->value->transactionFinished();
+    for (auto& it : m_objectStoreMap)
+        it.value->transactionFinished();
     m_objectStoreMap.clear();
-    for (IDBObjectStoreSet::iterator it = m_deletedObjectStores.begin(); it != m_deletedObjectStores.end(); ++it)
-        (*it)->transactionFinished();
+    for (auto& it : m_deletedObjectStores)
+        it->transactionFinished();
     m_deletedObjectStores.clear();
 
     WillBeHeapVector<RefPtrWillBeMember<EventTarget>> targets;