Bug 612455 - History.cpp should finalize statementCache on the background thread

Also fixes the favicon service to do this in a safer manner.
r=mak
a=blocking

toolkit/components/places/src/Helpers.h

@@ -46,6 +46,7 @@
 #include "mozilla/storage.h"
 #include "nsIURI.h"
 #include "nsThreadUtils.h"
+#include "nsProxyRelease.h"
 
 namespace mozilla {
 namespace places {
@@ -211,23 +212,33 @@ public:
    *
    * @param aStatementCache
    *        The statementCache that should be finalized.
+   * @param aOwner
+   *        The object that owns the statement cache.  This runnable will hold
+   *        a strong reference to it so aStatementCache will not disappear from
+   *        under us.
    */
   FinalizeStatementCacheProxy(
-    mozilla::storage::StatementCache<StatementType>& aStatementCache
+    mozilla::storage::StatementCache<StatementType>& aStatementCache,
+    nsISupports* aOwner
   )
   : mStatementCache(aStatementCache)
+  , mOwner(aOwner)
+  , mCallingThread(do_GetCurrentThread())
   {
   }
 
-  NS_IMETHOD
-  Run()
+  NS_IMETHOD Run()
   {
     mStatementCache.FinalizeStatements();
+    // Release the owner back on the calling thread.
+    (void)NS_ProxyRelease(mCallingThread, mOwner);
     return NS_OK;
   }
 
 protected:
   mozilla::storage::StatementCache<StatementType>& mStatementCache;
+  nsCOMPtr<nsISupports> mOwner;
+  nsCOMPtr<nsIThread> mCallingThread;
 };
 
 } // namespace places

toolkit/components/places/src/History.cpp

@@ -863,10 +863,6 @@ History::~History()
                  "Not all Links were removed before we disappear!");
   }
 #endif
-
-  // Places shutdown event may not occur, but we *must* clean up before History
-  // goes away.
-  Shutdown();
 }
 
 void
@@ -984,10 +980,18 @@ History::GetDBConn()
 void
 History::Shutdown()
 {
+  NS_ASSERTION(!mShuttingDown, "Shutdown was called more than once!");
+
   mShuttingDown = true;
 
   // Clean up our statements and connection.
-  syncStatements.FinalizeStatements();
+  nsISupports* obj = static_cast<IHistory*>(this);
+  nsCOMPtr<nsIRunnable> event =
+    new FinalizeStatementCacheProxy<mozIStorageStatement>(syncStatements, obj);
+  nsCOMPtr<nsIEventTarget> target = do_GetInterface(mDBConn);
+  if (target) {
+    (void)target->Dispatch(event, NS_DISPATCH_NORMAL);
+  }
 
   if (mReadOnlyDBConn) {
     if (mIsVisitedStatement) {

toolkit/components/places/src/nsFaviconService.cpp

@@ -942,7 +942,7 @@ nsFaviconService::FinalizeStatements() {
 
   // Finalize the statementCache on the correct thread.
   nsRefPtr<FinalizeStatementCacheProxy<mozIStorageStatement> > event =
-    new FinalizeStatementCacheProxy<mozIStorageStatement>(mSyncStatements);
+    new FinalizeStatementCacheProxy<mozIStorageStatement>(mSyncStatements, this);
   nsCOMPtr<nsIEventTarget> target = do_GetInterface(mDBConn);
   NS_ENSURE_TRUE(target, NS_ERROR_OUT_OF_MEMORY);
   nsresult rv = target->Dispatch(event, NS_DISPATCH_NORMAL);