Adds logging code to help figure out why test is crashing on bot

chrome/test/base/mash_browser_tests_main.cc

 // Copyright 2016 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 <algorithm>
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/debug/debugger.h"
 #include "base/memory/ptr_util.h"
@@ skipping 112 matching lines @@
 
   if (command_line.HasSwitch(switches::kChildProcess) &&
       !command_line.HasSwitch(MojoTestConnector::kTestSwitch)) {
     base::AtExitManager at_exit;
     shell::InitializeLogging();
     shell::WaitForDebuggerIfNecessary();
 #if !defined(OFFICIAL_BUILD) && defined(OS_WIN)
     base::RouteStdioToConsole(false);
 #endif
     *exit_code = shell::ChildProcessMain();
+    LOG(ERROR) << "child exit_code=" << *exit_code;

[msw, 2016/04/14 21:29:40]

optional nit: add comments to remove later here and below; cite bug?

     return true;
   }
 
   int default_jobs = std::max(1, base::SysInfo::NumberOfProcessors() / 2);
   MashTestLauncherDelegate delegate;
   // --single_process and no primoridal pipe token indicate we were run directly
   // from the command line. In this case we have to start up MojoShellConnection
   // as though we were embedded.
   content::MojoShellConnection::Factory shell_connection_factory;
   if (command_line.HasSwitch(content::kSingleProcessTestsFlag) &&
       !command_line.HasSwitch(switches::kPrimordialPipeToken)) {
     shell_connection_factory =
         base::Bind(&CreateMojoShellConnection, &delegate);
     content::MojoShellConnection::SetFactoryForTest(&shell_connection_factory);
   }
   *exit_code = LaunchChromeTests(default_jobs, &delegate, argc, argv);
+  LOG(ERROR) << "RunMashBrowserTests exit_code=" << *exit_code;
   return true;
 }