chrome: Cleanup class/struct forward declarations

chrome/test/base/in_process_browser_test.h

Index: chrome/test/base/in_process_browser_test.h
diff --git a/chrome/test/base/in_process_browser_test.h b/chrome/test/base/in_process_browser_test.h
index d73e8d3ff71042fbd1a14d2a47f72ac0e222fef1..c66260e59f6b3eb0129fa4961e320715d86cb594 100644
--- a/chrome/test/base/in_process_browser_test.h
+++ b/chrome/test/base/in_process_browser_test.h
@@ -40,10 +40,6 @@ class Profile;
 class ScopedBundleSwizzlerMac;
 #endif  // defined(OS_MACOSX)
 
-namespace content {
-class ContentRendererClient;
-}
-
 // Base class for tests wanting to bring up a browser in the unit test process.
 // Writing tests with InProcessBrowserTest is slightly different than that of
 // other tests. This is necessitated by InProcessBrowserTest running a message