exo: Ignore key events when the target is not an exo::Surface

When an event target is not an exo::Surface, let another handler process
the event.

BUG=b:135076290
TEST=Confirm arrow keys work correctly in a custom tab and a normal ARC
app (such as Google Docs)
TEST=exo_unittests --gtest_filter=KeyboardTest.OnKeyboardKey

Change-Id: I8218aeced9f5a7e15db55099da45ce4cd72e83b2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1659488
Commit-Queue: Jesse Schettler <jschettler@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Yuichiro Hanada <yhanada@chromium.org>
Cr-Commit-Position: refs/heads/master@{#670244}

components/exo/keyboard.cc

@@ -14,6 +14,7 @@
 #include "components/exo/keyboard_device_configuration_delegate.h"
 #include "components/exo/seat.h"
 #include "components/exo/shell_surface.h"
+#include "components/exo/shell_surface_util.h"
 #include "components/exo/surface.h"
 #include "components/exo/wm_helper.h"
 #include "ui/aura/client/aura_constants.h"
@@ -236,6 +237,14 @@ void Keyboard::OnKeyEvent(ui::KeyEvent* event) {
   if (event->is_repeat())
     return;
 
+  // If the event target is not an exo::Surface, let another handler process the
+  // event. This check may not be necessary once https://crbug.com/624168 is
+  // resolved.
+  if (!GetShellMainSurface(static_cast<aura::Window*>(event->target())) &&
+      !Surface::AsSurface(static_cast<aura::Window*>(event->target()))) {
+    return;
+  }
+
   TRACE_EXO_INPUT_EVENT(event);
 
   // Process reserved accelerators before sending it to client.

components/exo/keyboard_unittest.cc

@@ -238,6 +238,28 @@ TEST_F(KeyboardTest, OnKeyboardKey) {
   EXPECT_CALL(delegate, OnKeyboardKey(testing::_, ui::DomCode::US_W, false));
   generator.ReleaseKey(ui::VKEY_W, ui::EF_CONTROL_DOWN);
 
+  // Key events should be ignored when the focused window is not an
+  // exo::Surface.
+  auto window = CreateChildWindow(shell_surface->GetWidget()->GetNativeWindow(),
+                                  gfx::Rect(buffer_size));
+  // Moving the focus away will trigger the fallback path in GetEffectiveFocus.
+  // TODO(oshima): Consider removing the fallback path.
+  EXPECT_CALL(delegate, CanAcceptKeyboardEventsForSurface(surface.get()))
+      .WillOnce(testing::Return(true));
+  focus_client->FocusWindow(window.get());
+
+  EXPECT_CALL(delegate,
+              OnKeyboardKey(testing::_, ui::DomCode::ARROW_LEFT, true))
+      .Times(0);
+  seat.set_physical_code_for_currently_processing_event_for_testing(
+      ui::DomCode::ARROW_LEFT);
+  generator.PressKey(ui::VKEY_LEFT, 0);
+
+  EXPECT_CALL(delegate,
+              OnKeyboardKey(testing::_, ui::DomCode::ARROW_LEFT, false))
+      .Times(0);
+  generator.ReleaseKey(ui::VKEY_LEFT, 0);
+
   keyboard.reset();
 }