Enable autohide frame in Snapped ClientControlledShellSurface

Bug: 869429
Test: covered by unittest
Change-Id: I192d74e0dd467238af2bf0db7e7e37b5df69ed81
Reviewed-on: https://chromium-review.googlesource.com/1156881Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580007}

components/exo/client_controlled_shell_surface.cc

@@ -448,7 +448,8 @@ void ClientControlledShellSurface::SetCanMaximize(bool can_maximize) {
 void ClientControlledShellSurface::UpdateAutoHideFrame() {
   if (immersive_fullscreen_controller_) {
     bool enabled = (frame_type_ == SurfaceFrameType::AUTOHIDE &&
-                    GetWindowState()->IsMaximizedOrFullscreenOrPinned());
+                    (GetWindowState()->IsMaximizedOrFullscreenOrPinned() ||
+                     GetWindowState()->IsSnapped()));
     immersive_fullscreen_controller_->SetEnabled(
         ash::ImmersiveFullscreenController::WINDOW_TYPE_OTHER, enabled);
   }

components/exo/client_controlled_shell_surface_unittest.cc

@@ -1490,4 +1490,32 @@ TEST_F(ClientControlledShellSurfaceTest, AdjustBoundsLocally) {
   EXPECT_EQ(gfx::Rect(774, 0, 200, 300), requested_bounds);
 }
 
+TEST_F(ClientControlledShellSurfaceTest, SnappedInTabletMode) {
+  gfx::Size buffer_size(256, 256);
+  std::unique_ptr<Buffer> buffer(
+      new Buffer(exo_test_helper()->CreateGpuMemoryBuffer(buffer_size)));
+  std::unique_ptr<Surface> surface(new Surface);
+  auto shell_surface(
+      exo_test_helper()->CreateClientControlledShellSurface(surface.get()));
+  surface->Attach(buffer.get());
+  surface->Commit();
+  shell_surface->GetWidget()->Show();
+  auto* window = shell_surface->GetWidget()->GetNativeWindow();
+  auto* window_state = ash::wm::GetWindowState(window);
+
+  EnableTabletMode(true);
+
+  ash::wm::WMEvent event(ash::wm::WM_EVENT_SNAP_LEFT);
+  window_state->OnWMEvent(&event);
+  EXPECT_EQ(window_state->GetStateType(),
+            ash::mojom::WindowStateType::LEFT_SNAPPED);
+
+  ash::CustomFrameViewAsh* frame_view = static_cast<ash::CustomFrameViewAsh*>(
+      shell_surface->GetWidget()->non_client_view()->frame_view());
+  // Snapped window can also use auto hide.
+  surface->SetFrame(SurfaceFrameType::AUTOHIDE);
+  EXPECT_TRUE(frame_view->visible());
+  EXPECT_TRUE(frame_view->GetHeaderView()->in_immersive_mode());
+}
+
 }  // namespace exo