Abort if BrowserMainLoops fails to start a browser thread

content/browser/browser_main_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 "content/browser/browser_main_loop.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/files/file_util.h"
@@ skipping 1028 matching lines @@
     TRACE_EVENT0("startup",
       "BrowserMainLoop::BrowserThreadsStarted:InitSpeechRecognition");
     speech_recognition_manager_.reset(new SpeechRecognitionManagerImpl(
         audio_manager_.get(), media_stream_manager_.get()));
   }
 
   {
     TRACE_EVENT0(
         "startup",
         "BrowserMainLoop::BrowserThreadsStarted::InitUserInputMonitor");
-    user_input_monitor_ = media::UserInputMonitor::Create(
-        io_thread_->message_loop_proxy(), main_thread_->message_loop_proxy());
+    if (io_thread_->message_loop_proxy().get() != NULL &&

[Charlie Reis, 2014/09/11 23:10:30]

If we want to confirm that the cause of this crash is early shutdown, then
perhaps a better way is to check Thread::IsRunning() here instead of doing a
null check on message_loop_proxy.  Then we'll still notice (via crash reports)
if some other unknown issue is present.

[jiayl, 2014/09/11 23:55:37]

I tested it with your suggestion, but IsRunning() is false even during normal
startup when the TaskRunner is not NULL.

+        main_thread_->message_loop_proxy().get() != NULL) {
+      user_input_monitor_ = media::UserInputMonitor::Create(
+          io_thread_->message_loop_proxy(), main_thread_->message_loop_proxy());

[Charlie Reis, 2014/09/11 23:10:30]

Can this use task_runner() instead of message_loop_proxy()?  I noticed that the
latter is deprecated according to thread.h, and the Create call already has the
right contract for it.

[jiayl, 2014/09/11 23:55:37]

Will do.

+    }
   }
 
   {
     TRACE_EVENT0("startup",
                  "BrowserMainLoop::BrowserThreadsStarted::TimeZoneMonitor");
     time_zone_monitor_ = TimeZoneMonitor::Create();
   }
 
   // Alert the clipboard class to which threads are allowed to access the
   // clipboard:
@@ skipping 133 matching lines @@
                              &BrowserMainLoop::EndStartupTracing);
 }
 
 void BrowserMainLoop::EndStartupTracing() {
   is_tracing_startup_ = false;
   TracingController::GetInstance()->DisableRecording(
       startup_trace_file_, base::Bind(&OnStoppedStartupTracing));
 }
 
 }  // namespace content