updater_state_unittests: don't lookup a nil map on non-Windows platforms.

components/update_client/updater_state_unittest.cc

Index: components/update_client/updater_state_unittest.cc
diff --git a/components/update_client/updater_state_unittest.cc b/components/update_client/updater_state_unittest.cc
index 7627b46a22d8ba8ab8cdcbc94e68d0dad9653059..9d34ba5785df71c23cff9a580e7ee8a3925b31ca 100644
--- a/components/update_client/updater_state_unittest.cc
+++ b/components/update_client/updater_state_unittest.cc
@@ -41,7 +41,7 @@ TEST_F(UpdaterStateTest, Serialize) {
   EXPECT_STREQ("1", attributes.at("autoupdatecheckenabled").c_str());
   EXPECT_STREQ("1", attributes.at("updatepolicy").c_str());
 
-#if defined(GOOGLE_CHROME_BUILD)
+#if defined(GOOGLE_CHROME_BUILD) && defined(OS_WIN)
   // The name of the Windows updater for Chrome.
   EXPECT_STREQ("Omaha", UpdaterState::GetState(false)->at("name").c_str());
 #endif  // GOOGLE_CHROME_BUILD