Add base::RunLoop and update ui_test_utils to use it to reduce flakiness

base/message_loop.cc

 // Copyright (c) 2012 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_loop.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 117 matching lines @@
 
 MessageLoop::MessageLoop(Type type)
     : type_(type),
       nestable_tasks_allowed_(true),
       exception_restoration_(false),
       message_histogram_(NULL),
       state_(NULL),
 #ifdef OS_WIN
       os_modal_loop_(false),
 #endif  // OS_WIN
-      next_sequence_num_(0) {
+      next_sequence_num_(0),
+      current_run_state_id_(0) {
   DCHECK(!current()) << "should only have one message loop per thread";
   lazy_tls_ptr.Pointer()->Set(this);
 
   message_loop_proxy_ = new base::MessageLoopProxyImpl();
   thread_task_runner_handle_.reset(
       new base::ThreadTaskRunnerHandle(message_loop_proxy_));
 
 // TODO(rvargas): Get rid of the OS guards.
 #if defined(OS_WIN)
 #define MESSAGE_PUMP_UI new base::MessagePumpForUI()
@@ skipping 157 matching lines @@
   AutoRunState save_state(this);
   RunHandler();
 }
 
 void MessageLoop::RunAllPending() {
   AutoRunState save_state(this);
   state_->quit_received = true;  // Means run until we would otherwise block.
   RunHandler();
 }
 
-void MessageLoop::Quit() {
+void MessageLoop::QuitWhenIdle() {
   DCHECK_EQ(this, current());
   if (state_) {
     state_->quit_received = true;
   } else {
     NOTREACHED() << "Must be inside Run to call Quit";
   }
 }
 
 void MessageLoop::QuitNow() {
   DCHECK_EQ(this, current());
   if (state_) {
     pump_->Quit();
   } else {
     NOTREACHED() << "Must be inside Run to call Quit";
   }
 }
 
-static void QuitCurrent() {
-  MessageLoop::current()->Quit();
+void MessageLoop::QuitNowByID(int run_id) {
+  DCHECK_EQ(this, current());
+  if (!state_)
+    return;
+  if (state_->run_state_id == run_id)
+    QuitNow();
+
+  // Search back through RunStates for run_id.
+  RunState* run_state = state_;
+  while (run_state) {
+    if (run_state->run_state_id == run_id) {
+      run_state->quit_now_received = true;
+      break;
+    }
+    run_state = run_state->previous_state;
+  }
+}
+
+static void QuitWhenIdleCurrent() {
+  MessageLoop::current()->QuitWhenIdle();
+}
+
+static void QuitNowCurrent() {
+  MessageLoop::current()->QuitNow();
+}
+
+static void QuitNowByIDCurrent(int run_id) {

[jar (doing other things), 2012/06/14 04:50:29]

nit: I think the word "current" is in the wrong place, as it seems to be linked
to "IdCurrent".  Perhaps better is:

QuitCurrentNowByID

<sigh> all names are hard to read... but that might be an improvement.  WDYT?

[jbates, 2012/06/15 02:20:38]

Done.

+  MessageLoop::current()->QuitNowByID(run_id);
 }
 
 // static
-base::Closure MessageLoop::QuitClosure() {
-  return base::Bind(&QuitCurrent);
+base::Closure MessageLoop::QuitWhenIdleClosure() {
+  return base::Bind(&QuitWhenIdleCurrent);
+}
+
+// static
+base::Closure MessageLoop::QuitNowClosure() {
+  return base::Bind(&QuitNowCurrent);
+}
+
+// static
+base::Closure MessageLoop::QuitNowByIDClosure(int run_id) {
+  return base::Bind(&QuitNowByIDCurrent, run_id);
 }
 
 void MessageLoop::SetNestableTasksAllowed(bool allowed) {
   if (nestable_tasks_allowed_ != allowed) {
     nestable_tasks_allowed_ = allowed;
     if (!nestable_tasks_allowed_)
       return;
     // Start the native pump if we are not already pumping.
     pump_->ScheduleWork();
   }
@@ skipping 362 matching lines @@
     void(*releaser)(const void*),
     const void* object) {
   PostNonNestableTask(from_here, base::Bind(releaser, object));
 }
 
 //------------------------------------------------------------------------------
 // MessageLoop::AutoRunState
 
 MessageLoop::AutoRunState::AutoRunState(MessageLoop* loop) : loop_(loop) {
   // Make the loop reference us.
-  previous_state_ = loop_->state_;
-  if (previous_state_) {
-    run_depth = previous_state_->run_depth + 1;
+  previous_state = loop_->state_;
+  if (previous_state) {
+    run_depth = previous_state->run_depth + 1;
   } else {
     run_depth = 1;
   }
   loop_->state_ = this;
 
+  run_state_id = ++loop_->current_run_state_id_;
+
   // Initialize the other fields:
   quit_received = false;
+  quit_now_received = false;
 #if !defined(OS_MACOSX) && !defined(OS_ANDROID)
   dispatcher = NULL;
 #endif
 }
 
 MessageLoop::AutoRunState::~AutoRunState() {
-  loop_->state_ = previous_state_;
+  loop_->state_ = previous_state;
+  if (previous_state && previous_state->quit_now_received)
+    MessageLoop::current()->QuitNow();
 }
 
 //------------------------------------------------------------------------------
 // MessageLoopForUI
 
 #if defined(OS_WIN)
 void MessageLoopForUI::DidProcessMessage(const MSG& message) {
   pump_win()->DidProcessMessage(message);
 }
 #endif  // defined(OS_WIN)
@@ skipping 51 matching lines @@
                                            Watcher *delegate) {
   return pump_libevent()->WatchFileDescriptor(
       fd,
       persistent,
       static_cast<base::MessagePumpLibevent::Mode>(mode),
       controller,
       delegate);
 }
 
 #endif