Fix some extern usage in .cc files.

content/public/browser/browser_main_runner.h

Index: content/public/browser/browser_main_runner.h
diff --git a/content/public/browser/browser_main_runner.h b/content/public/browser/browser_main_runner.h
index dcde509e583aedd2bccb70e3ace8a0def853b09d..9eb6afbbaa27514683c1aa83d3540b96727e226b 100644
--- a/content/public/browser/browser_main_runner.h
+++ b/content/public/browser/browser_main_runner.h
@@ -20,6 +20,9 @@ class CONTENT_EXPORT BrowserMainRunner {
   // Create a new BrowserMainRunner object.
   static BrowserMainRunner* Create();
 
+  // Returns true if the BrowserMainRunner has exited the main loop.
+  static bool ExitedMainMessageLoop();

[ncarter (slow), 2015/08/28 21:27:20]

Does this need to be exposed outside of content?

[Lei Zhang, 2015/08/28 22:36:21]

As is, no. content/browser/browser_main_runner.h does not exist though.

+
   // Initialize all necessary browser state. The |parameters| values will be
   // copied. Returning a non-negative value indicates that initialization
   // failed, and the returned value is used as the exit code for the process.