signin: pull basic SigninManager functionality into new SigninManagerBase class.

chrome/test/base/chrome_render_view_host_test_harness.cc

Index: chrome/test/base/chrome_render_view_host_test_harness.cc
diff --git a/chrome/test/base/chrome_render_view_host_test_harness.cc b/chrome/test/base/chrome_render_view_host_test_harness.cc
index e340ee7dff094fcbe620844780a355b62f73d9a7..ea5522495fa378af1f3fbd21ea6db6e8ff4e8813 100644
--- a/chrome/test/base/chrome_render_view_host_test_harness.cc
+++ b/chrome/test/base/chrome_render_view_host_test_harness.cc
@@ -36,7 +36,11 @@ RenderViewHostTester* ChromeRenderViewHostTestHarness::rvh_tester() {
 }
 
 static ProfileKeyedService* BuildSigninManagerFake(Profile* profile) {
+#if defined (OS_CHROMEOS)
+  return new FakeSigninManagerBase(profile);
+#else
   return new FakeSigninManager(profile);
+#endif
 }
 
 void ChromeRenderViewHostTestHarness::SetUp() {