[Mac]Port browser_keyevents_browsertest.cc and browser_focus_uitest.cc to Mac.

chrome/test/ui_test_utils_linux.cc

Index: chrome/test/ui_test_utils_linux.cc
diff --git a/chrome/test/ui_test_utils_linux.cc b/chrome/test/ui_test_utils_linux.cc
index 5878086baf0f53fdfd570cd1fcef541c95937bcf..e9d29dcdd870ebcd0d2952f659004251a1bd14a5 100644
--- a/chrome/test/ui_test_utils_linux.cc
+++ b/chrome/test/ui_test_utils_linux.cc
@@ -85,4 +85,12 @@ void ClickOnView(const Browser* browser, ViewID vid) {
   RunMessageLoop();
 }
 
+void HideNativeWindow(gfx::NativeWindow window) {
+  gtk_widget_hide(GTK_WIDGET(window));
+}
+
+void ShowAndFocusNativeWindow(gfx::NativeWindow window) {
+  gtk_window_present(GTK_WINDOW(window));
+}
+
 }  // namespace ui_test_utils