Try more (um, all) nonnestable work when falling out of a nested run loop

base/message_pump_mac.mm

 // Copyright (c) 2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/message_pump_mac.h"
 
 #import <AppKit/AppKit.h>
 #import <Foundation/Foundation.h>
 #include <float.h>
 
@@ skipping 245 matching lines @@
 
 // Called from the run loop.
 // static
 void MessagePumpCFRunLoopBase::RunNestingDeferredWorkSource(void* info) {
   MessagePumpCFRunLoopBase* self = static_cast<MessagePumpCFRunLoopBase*>(info);
   self->RunNestingDeferredWork();
 }
 
 // Called by MessagePumpCFRunLoopBase::RunNestingDeferredWorkSource.
 bool MessagePumpCFRunLoopBase::RunNestingDeferredWork() {
+  // Immediately try work in priority order.
   if (!RunWork()) {
     if (!RunDelayedWork()) {
       if (!RunIdleWork()) {
         return false;
       }
+    } else {
+      // There was no work, and delayed work was done.  Arrange for the loop
+      // to try non-nestable idle work on a subsequent pass.
+      CFRunLoopSourceSignal(idle_work_source_);
     }
+  } else {
+    // Work was done.  Arrange for the loop to try non-nestable delayed and
+    // idle work on a subsequent pass.
+    CFRunLoopSourceSignal(delayed_work_source_);
+    CFRunLoopSourceSignal(idle_work_source_);
   }
 
   return true;
 }
 
 // Called from the run loop.
 // static
 void MessagePumpCFRunLoopBase::PreWaitObserver(CFRunLoopObserverRef observer,
                                                CFRunLoopActivity activity,
                                                void* info) {
@@ skipping 179 matching lines @@
 // static
 MessagePump* MessagePumpMac::Create() {
   if ([NSThread isMainThread]) {
     return new MessagePumpNSApplication;
   }
 
   return new MessagePumpNSRunLoop;
 }
 
 }  // namespace base