mus: Don't allow SetEventObserver to monitor key events

components/mus/ws/window_tree_unittest.cc

Index: components/mus/ws/window_tree_unittest.cc
diff --git a/components/mus/ws/window_tree_unittest.cc b/components/mus/ws/window_tree_unittest.cc
index 59974e80de9694d12fcb3feebfd279accb928be8..ab51cb4dd25d32dc93b2305431b49da717e88e7f 100644
--- a/components/mus/ws/window_tree_unittest.cc
+++ b/components/mus/ws/window_tree_unittest.cc
@@ -384,14 +384,19 @@ TEST_F(WindowTreeTest, SetEventObserverWrongUser) {
   ASSERT_EQ(0u, other_binding->client()->tracker()->changes()->size());
 }
 
-// Tests that an event observer can receive events that have no target window.
-TEST_F(WindowTreeTest, SetEventObserverNoTarget) {

[James Cook, 2016/05/25 20:59:41]

I removed this test because the remaining event types supported by
SetEventObserver always have a target -- they are all mouse or touch events, and
if they don't hit a client window they are dispatched to the root window.

+// Tests that an event observer cannot observe keystrokes.
+TEST_F(WindowTreeTest, SetEventObserverKeyEventsDisallowed) {
   WindowTreeTestApi(wm_tree()).SetEventObserver(
-      CreateEventMatcher(mojom::EventType::KEY_RELEASED), 111u);
-  ui::KeyEvent key(ui::ET_KEY_RELEASED, ui::VKEY_A, ui::EF_NONE);
-  DispatchEventAndAckImmediately(key);
-  EXPECT_EQ("EventObserved event_action=2 event_observer_id=111",
-            SingleChangeToDescription(*wm_client()->tracker()->changes()));
+      CreateEventMatcher(mojom::EventType::KEY_PRESSED), 111u);
+  ui::KeyEvent key_pressed(ui::ET_KEY_PRESSED, ui::VKEY_A, ui::EF_NONE);
+  DispatchEventAndAckImmediately(key_pressed);
+  EXPECT_EQ(0u, wm_client()->tracker()->changes()->size());
+
+  WindowTreeTestApi(wm_tree()).SetEventObserver(
+      CreateEventMatcher(mojom::EventType::KEY_RELEASED), 222u);
+  ui::KeyEvent key_released(ui::ET_KEY_RELEASED, ui::VKEY_A, ui::EF_NONE);
+  DispatchEventAndAckImmediately(key_released);
+  EXPECT_EQ(0u, wm_client()->tracker()->changes()->size());
 }
 
 TEST_F(WindowTreeTest, CursorChangesWhenMouseOverWindowAndWindowSetsCursor) {