tablet: Disallow swipe down on shelf to auto hide.

Auto hide state can still be reached by full screening an app (F4 or app requests).

Test: ash_unittests ShelfLayoutManagerTest.SwipingUpOnShelfInTabletModeForFullscreenAppList
Bug: 801684
Change-Id: I4da8d7b7ecf7d25310f3f55861bf5f82b6cd7f23
Reviewed-on: https://chromium-review.googlesource.com/939646
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541031}

ash/shelf/shelf_layout_manager.cc

@@ -86,6 +86,12 @@ bool IsAppListWindow(const aura::Window* window) {
   return parent && parent->id() == kShellWindowId_AppListContainer;
 }
 
+bool IsTabletModeEnabled() {
+  return Shell::Get()
+      ->tablet_mode_controller()
+      ->IsTabletModeWindowManagerEnabled();
+}
+
 }  // namespace
 
 // ShelfLayoutManager::UpdateShelfObserver -------------------------------------
@@ -1192,7 +1198,7 @@ void ShelfLayoutManager::CompleteGestureDrag(
   // behavior if there is at least one window visible.
   gesture_drag_status_ = GESTURE_DRAG_COMPLETE_IN_PROGRESS;
   if (shelf_->auto_hide_behavior() != new_auto_hide_behavior &&
-      HasVisibleWindow()) {
+      HasVisibleWindow() && !IsTabletModeEnabled()) {
     shelf_->SetAutoHideBehavior(new_auto_hide_behavior);
   } else {
     UpdateVisibilityState();
@@ -1221,9 +1227,7 @@ void ShelfLayoutManager::CompleteAppListDrag(
   } else {
     // Snap the app list to corresponding state according to the snapping
     // thresholds.
-    if (Shell::Get()
-            ->tablet_mode_controller()
-            ->IsTabletModeWindowManagerEnabled()) {
+    if (IsTabletModeEnabled()) {
       app_list_state = launcher_above_shelf_bottom_amount_ >
                                kAppListDragSnapToFullscreenThreshold
                            ? AppListState::FULLSCREEN_ALL_APPS

ash/shelf/shelf_layout_manager_unittest.cc

@@ -31,6 +31,7 @@
 #include "ash/wm/tablet_mode/tablet_mode_controller.h"
 #include "ash/wm/window_state.h"
 #include "ash/wm/window_util.h"
+#include "ash/wm/wm_event.h"
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
@@ -1484,12 +1485,20 @@ TEST_F(ShelfLayoutManagerTest,
   Shell* shell = Shell::Get();
   shell->tablet_mode_controller()->EnableTabletModeWindowManager(true);
   Shelf* shelf = GetPrimaryShelf();
+  GetShelfLayoutManager()->LayoutShelf();
   EXPECT_EQ(SHELF_ALIGNMENT_BOTTOM, shelf->alignment());
   EXPECT_EQ(SHELF_AUTO_HIDE_BEHAVIOR_NEVER, shelf->auto_hide_behavior());
   EXPECT_EQ(SHELF_VISIBLE, shelf->GetVisibilityState());
 
-  // Note: A window must be visible in order to hide the shelf.
-  views::Widget* widget = CreateTestWidget();
+  // Note: A window must be visible in order to hide the shelf. The test will
+  // make the window fullscreened, so make the window resizeable and
+  // maximizable.
+  std::unique_ptr<aura::Window> window(
+      AshTestBase::CreateTestWindow(gfx::Rect(0, 0, 400, 400)));
+  window->SetProperty(aura::client::kResizeBehaviorKey,
+                      ui::mojom::kResizeBehaviorCanResize |
+                          ui::mojom::kResizeBehaviorCanMaximize);
+  wm::ActivateWindow(window.get());
 
   ui::test::EventGenerator& generator(GetEventGenerator());
   constexpr base::TimeDelta kTimeDelta = base::TimeDelta::FromMilliseconds(100);
@@ -1527,35 +1536,51 @@ TEST_F(ShelfLayoutManagerTest,
   GetAppListTestHelper()->WaitUntilIdle();
   GetAppListTestHelper()->CheckVisibility(false);
   GetAppListTestHelper()->CheckState(app_list::AppListViewState::CLOSED);
+  GetShelfLayoutManager()->UpdateVisibilityState();
   EXPECT_EQ(SHELF_VISIBLE, shelf->GetVisibilityState());
 
-  // Swiping down on the shelf should hide it.
+  // Swiping down on the shelf should do nothing as tablet mode disables auto
+  // hiding the shelf by swiping down.
   end = start + delta;
   generator.GestureScrollSequence(start, end, kTimeDelta, kNumScrollSteps);
+  EXPECT_EQ(SHELF_VISIBLE, shelf->GetVisibilityState());
+
+  // Verify that the shelf can still enter auto hide if the window requests to
+  // be fullscreened.
+  wm::WindowState* window_state = wm::GetWindowState(window.get());
+  const wm::WMEvent event(wm::WM_EVENT_TOGGLE_FULLSCREEN);
+  window_state->OnWMEvent(&event);
+  window_state->SetHideShelfWhenFullscreen(false);
+  window_state->SetInImmersiveFullscreen(true);
+  GetShelfLayoutManager()->UpdateVisibilityState();
   EXPECT_EQ(SHELF_AUTO_HIDE, shelf->GetVisibilityState());
   EXPECT_EQ(SHELF_AUTO_HIDE_HIDDEN, shelf->GetAutoHideState());
-  EXPECT_EQ(SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS, shelf->auto_hide_behavior());
+  EXPECT_EQ(SHELF_AUTO_HIDE_BEHAVIOR_NEVER, shelf->auto_hide_behavior());
 
   // Swiping up should show the shelf but not the app list if shelf is hidden.
   generator.GestureScrollSequence(end, start, kTimeDelta, kNumScrollSteps);
   GetAppListTestHelper()->WaitUntilIdle();
   GetAppListTestHelper()->CheckVisibility(false);
   GetAppListTestHelper()->CheckState(app_list::AppListViewState::CLOSED);
-  EXPECT_EQ(SHELF_VISIBLE, shelf->GetVisibilityState());
+  EXPECT_EQ(SHELF_AUTO_HIDE, shelf->GetVisibilityState());
+  EXPECT_EQ(SHELF_AUTO_HIDE_SHOWN, shelf->GetAutoHideState());
   EXPECT_EQ(SHELF_AUTO_HIDE_BEHAVIOR_NEVER, shelf->auto_hide_behavior());
 
   // Swiping down should hide the shelf.
   generator.GestureScrollSequence(start, end, kTimeDelta, kNumScrollSteps);
   EXPECT_EQ(SHELF_AUTO_HIDE, shelf->GetVisibilityState());
   EXPECT_EQ(SHELF_AUTO_HIDE_HIDDEN, shelf->GetAutoHideState());
-  EXPECT_EQ(SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS, shelf->auto_hide_behavior());
+  EXPECT_EQ(SHELF_AUTO_HIDE_BEHAVIOR_NEVER, shelf->auto_hide_behavior());
+
+  // Verify that after toggling fullscreen to off, the shelf is visible.
+  window_state->OnWMEvent(&event);
+  EXPECT_EQ(SHELF_VISIBLE, shelf->GetVisibilityState());
 
   // Minimize the visible window, the shelf should be shown if there are no
   // visible windows, even in auto-hide mode.
-  widget->Minimize();
-  EXPECT_EQ(SHELF_AUTO_HIDE, shelf->GetVisibilityState());
-  EXPECT_EQ(SHELF_AUTO_HIDE_SHOWN, shelf->GetAutoHideState());
-  EXPECT_EQ(SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS, shelf->auto_hide_behavior());
+  window_state->Minimize();
+  EXPECT_EQ(SHELF_VISIBLE, shelf->GetVisibilityState());
+  EXPECT_EQ(SHELF_AUTO_HIDE_BEHAVIOR_NEVER, shelf->auto_hide_behavior());
 
   // Swiping up on the shelf in this state should open the app list.
   delta.set_y(ShelfLayoutManager::kAppListDragSnapToFullscreenThreshold + 10);