Support renaming of IndexedDB indexes and object stores.

third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp

Index: third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp
diff --git a/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp b/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp
index aa6524d1ebddae195ea237a791b8b3d7d2c62beb..c3ea8d4d7d32592d72c942cd6a95a97e5d7005ea 100644
--- a/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp
+++ b/third_party/WebKit/Source/modules/indexeddb/IDBTransaction.cpp
@@ -191,6 +191,19 @@ void IDBTransaction::objectStoreDeleted(const String& name)
     }
 }
 
+void IDBTransaction::objectStoreWillBeRenamed(const String& oldName, const String& newName)

[jsbell, 2016/09/07 17:16:14]

Here we don't need the id... but it still seems like passing (id, newName) would
be more natural. But that's just me.

[pwnall, 2016/09/07 22:43:52]

objectStoreDeleted() also takes in the store's name. Should I look into changing
both of them?

+{
+    DCHECK(m_state != Finished);
+    DCHECK(isVersionChange());
+
+    DCHECK(!m_objectStoreMap.contains(newName));
+    DCHECK(m_objectStoreMap.contains(oldName)) << "The object store had to be accessed in order to be renamed.";
+
+    IDBObjectStoreMap::iterator it = m_objectStoreMap.find(oldName);
+    m_objectStoreMap.set(newName, it->value);
+    m_objectStoreMap.remove(oldName);
+}
+
 void IDBTransaction::setActive(bool active)
 {
     DCHECK_NE(m_state, Finished) << "A finished transaction tried to setActive(" << (active ? "true" : "false") << ")";