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

chrome/test/base/mash_browser_tests_main.cc

Index: chrome/test/base/mash_browser_tests_main.cc
diff --git a/chrome/test/base/mash_browser_tests_main.cc b/chrome/test/base/mash_browser_tests_main.cc
index 0b522699e102cc56bc232155d79c22b130852070..f06679473d8bed709fcc0f885c2d6e246787f109 100644
--- a/chrome/test/base/mash_browser_tests_main.cc
+++ b/chrome/test/base/mash_browser_tests_main.cc
@@ -130,6 +130,7 @@ bool RunMashBrowserTests(int argc, char** argv, int* exit_code) {
     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;
   }
 
@@ -146,5 +147,6 @@ bool RunMashBrowserTests(int argc, char** argv, int* exit_code) {
     content::MojoShellConnection::SetFactoryForTest(&shell_connection_factory);
   }
   *exit_code = LaunchChromeTests(default_jobs, &delegate, argc, argv);
+  LOG(ERROR) << "RunMashBrowserTests exit_code=" << *exit_code;
   return true;
 }