Upstream RunBlockingPoolTask().

content/public/test/test_utils.cc

Index: content/public/test/test_utils.cc
diff --git a/content/public/test/test_utils.cc b/content/public/test/test_utils.cc
index ae45762dab52550be6d1c7008b24dc8b224f5bf0..c90a6c0a3da5ce1f9d9be38cefe002d5f1a1a6ea 100644
--- a/content/public/test/test_utils.cc
+++ b/content/public/test/test_utils.cc
@@ -49,7 +49,7 @@ void RunAllPendingMessageAndSendQuit(BrowserThread::ID thread_id,
   BrowserThread::PostTask(thread_id, FROM_HERE, quit_task);
 }
 
-// Class used handle result callbacks for ExecuteScriptAndGetValue.
+// Class used to handle result callbacks for ExecuteScriptAndGetValue.
 class ScriptCallback {
  public:
   ScriptCallback() { }
@@ -70,6 +70,27 @@ void ScriptCallback::ResultCallback(const base::Value* result) {
   base::MessageLoop::current()->Quit();
 }
 
+// Monitors if any task is processed by the message loop.
+class TaskObserver : public base::MessageLoop::TaskObserver {
+ public:
+  TaskObserver() : processed_(false) {}
+  virtual ~TaskObserver() {}
+
+  // MessageLoop::TaskObserver overrides.
+  virtual void WillProcessTask(const base::PendingTask& pending_task) OVERRIDE {
+  }
+  virtual void DidProcessTask(const base::PendingTask& pending_task) OVERRIDE {
+    processed_ = true;
+  }
+
+  // Returns true if any task was processed.
+  bool processed() const { return processed_; }
+
+ private:
+  bool processed_;
+  DISALLOW_COPY_AND_ASSIGN(TaskObserver);
+};
+
 // Adapter that makes a WindowedNotificationObserver::ConditionTestCallback from
 // a WindowedNotificationObserver::ConditionTestCallbackWithoutSourceAndDetails
 // by ignoring the notification source and details.
@@ -129,6 +150,20 @@ void RunAllPendingInMessageLoop(BrowserThread::ID thread_id) {
   RunThisRunLoop(&run_loop);
 }
 
+void RunAllBlockingPoolTasksUntilIdle() {
+  while (true) {
+    TaskObserver task_observer;

[hashimoto, 2014/07/15 05:49:40]

nit: task_observer should be declared and initialized just before
AddTaskObserver().

[mtomasz, 2014/07/15 05:59:16]

Done.

+    content::BrowserThread::GetBlockingPool()->FlushForTesting();
+
+    base::MessageLoop::current()->AddTaskObserver(&task_observer);
+    base::RunLoop().RunUntilIdle();
+    base::MessageLoop::current()->RemoveTaskObserver(&task_observer);
+
+    if (!task_observer.processed())
+      break;
+  }
+}
+
 base::Closure GetQuitTaskForRunLoop(base::RunLoop* run_loop) {
   return base::Bind(&DeferredQuitRunLoop, run_loop->QuitClosure(),
                     kNumQuitDeferrals);