shelf: Update shelf auto hide state for home launcher.

Test: added test
Bug: 850630
Change-Id: I50796ab56aa2888bd77d98389a7de876f42aa0d8
Reviewed-on: https://chromium-review.googlesource.com/1179303Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584078}

ash/app_list/app_list_presenter_delegate_unittest.cc

@@ -36,6 +36,7 @@
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/test/scoped_feature_list.h"
+#include "ui/aura/client/aura_constants.h"
 #include "ui/aura/test/test_windows.h"
 #include "ui/aura/window.h"
 #include "ui/display/display.h"
@@ -502,6 +503,23 @@ TEST_F(AppListPresenterDelegateTest, ShelfBackgroundWithHomeLauncher) {
             shelf_layout_manager->GetShelfBackgroundType());
 }
 
+// Tests that the bottom shelf is auto hidden when a window is fullscreened in
+// tablet mode (home launcher is shown behind).
+TEST_F(AppListPresenterDelegateTest, ShelfAutoHiddenWhenFullscreen) {
+  GetAppListTestHelper()->ShowAndRunLoop(GetPrimaryDisplayId());
+  EnableTabletMode(true);
+  Shelf* shelf =
+      Shelf::ForWindow(Shell::GetRootWindowForDisplayId(GetPrimaryDisplayId()));
+  EXPECT_EQ(ShelfVisibilityState::SHELF_VISIBLE, shelf->GetVisibilityState());
+
+  // Create and fullscreen a window. The shelf should be auto hidden.
+  auto window = CreateTestWindow();
+  window->SetProperty(aura::client::kShowStateKey, ui::SHOW_STATE_FULLSCREEN);
+  EXPECT_EQ(ShelfVisibilityState::SHELF_AUTO_HIDE, shelf->GetVisibilityState());
+  EXPECT_EQ(ShelfAutoHideState::SHELF_AUTO_HIDE_HIDDEN,
+            shelf->GetAutoHideState());
+}
+
 // Tests that the peeking app list closes if the user taps or clicks outside
 // its bounds.
 TEST_P(AppListPresenterDelegateTest, TapAndClickOutsideClosesPeekingAppList) {

ash/shelf/shelf_layout_manager.cc

@@ -980,8 +980,12 @@ ShelfAutoHideState ShelfLayoutManager::CalculateAutoHideState(
   if (visibility_state != SHELF_AUTO_HIDE)
     return SHELF_AUTO_HIDE_HIDDEN;
 
-  if (shelf_widget_->IsShowingAppList())
+  if (shelf_widget_->IsShowingAppList() &&
+      !Shell::Get()
+           ->app_list_controller()
+           ->IsHomeLauncherEnabledInTabletMode()) {
     return SHELF_AUTO_HIDE_SHOWN;
+  }
 
   if (shelf_widget_->status_area_widget() &&
       shelf_widget_->status_area_widget()->ShouldShowShelf())