Made tablet mode switch shortcut and test API work on the device

* Introduced TabletModeBehavior struct that controls how
 TabletModeController controls tablet mode.
* Separate Forced mode, test mode and Dev mode (shortcut) as
 they requires slightly different behaviors.

* Remove the debug code from accelerometer reader and
move the test handling code to TabletModeController.

Bug: 963990
Test: manual. enable debug shortcut and ctrl-alt-shit-t on the device.
Change-Id: I4aeeb8f5c20991c9f46e855538e4d1970ca4cc02
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1655039
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672773}

ash/accelerators/debug_commands.cc

@@ -168,7 +168,7 @@ void HandleToggleTouchscreen() {
 
 void HandleToggleTabletMode() {
   TabletModeController* controller = Shell::Get()->tablet_mode_controller();
-  controller->SetEnabledForTest(!controller->InTabletMode());
+  controller->SetEnabledForDev(!controller->InTabletMode());
 }
 
 void HandleTriggerCrash() {

ash/accelerometer/accelerometer_reader.cc

@@ -724,23 +724,19 @@ void AccelerometerReader::Initialize(
 }
 
 void AccelerometerReader::AddObserver(Observer* observer) {
-  if (accelerometer_file_reader_)
-    accelerometer_file_reader_->AddObserver(observer);
+  accelerometer_file_reader_->AddObserver(observer);
 }
 
 void AccelerometerReader::RemoveObserver(Observer* observer) {
-  if (accelerometer_file_reader_)
-    accelerometer_file_reader_->RemoveObserver(observer);
+  accelerometer_file_reader_->RemoveObserver(observer);
 }
 
 void AccelerometerReader::StartListenToTabletModeController() {
-  if (accelerometer_file_reader_)
-    accelerometer_file_reader_->StartListenToTabletModeController();
+  accelerometer_file_reader_->StartListenToTabletModeController();
 }
 
 void AccelerometerReader::StopListenToTabletModeController() {
-  if (accelerometer_file_reader_)
-    accelerometer_file_reader_->StopListenToTabletModeController();
+  accelerometer_file_reader_->StopListenToTabletModeController();
 }
 
 AccelerometerReader::AccelerometerReader()
@@ -748,11 +744,4 @@ AccelerometerReader::AccelerometerReader()
 
 AccelerometerReader::~AccelerometerReader() = default;
 
-void AccelerometerReader::DisableForTest() {
-  if (accelerometer_file_reader_) {
-    accelerometer_file_reader_->StopListenToTabletModeController();
-    accelerometer_file_reader_.reset();
-  }
-}
-
 }  // namespace ash

ash/accelerometer/accelerometer_reader.h

@@ -49,10 +49,6 @@ class ASH_EXPORT AccelerometerReader {
   void StartListenToTabletModeController();
   void StopListenToTabletModeController();
 
-  void DisableForTest();
-
-  bool is_disabled() const { return !accelerometer_file_reader_; }
-
  protected:
   AccelerometerReader();
   virtual ~AccelerometerReader();

ash/public/cpp/ash_switches.cc

@@ -69,7 +69,6 @@ const char kAshPowerButtonPosition[] = "ash-power-button-position";
 const char kAshUiMode[] = "force-tablet-mode";
 
 // Values for the kAshUiMode flag.
-const char kAshUiModeAuto[] = "auto";
 const char kAshUiModeClamshell[] = "clamshell";
 const char kAshUiModeTablet[] = "touch_view";
 

ash/public/cpp/ash_switches.h

@@ -29,7 +29,6 @@ ASH_PUBLIC_EXPORT extern const char kAshEnableWaylandServer[];
 ASH_PUBLIC_EXPORT extern const char kAshForceEnableStylusTools[];
 ASH_PUBLIC_EXPORT extern const char kAshPowerButtonPosition[];
 ASH_PUBLIC_EXPORT extern const char kAshUiMode[];
-ASH_PUBLIC_EXPORT extern const char kAshUiModeAuto[];
 ASH_PUBLIC_EXPORT extern const char kAshUiModeClamshell[];
 ASH_PUBLIC_EXPORT extern const char kAshUiModeTablet[];
 ASH_PUBLIC_EXPORT extern const char kAshHideNotificationsForFactory[];

ash/shell_test_api.cc

@@ -187,7 +187,6 @@ bool ShellTestApi::IsSystemModalWindowOpen() {
 }
 
 void ShellTestApi::SetTabletModeEnabledForTest(bool enable) {
-  AccelerometerReader::GetInstance()->DisableForTest();
   shell_->tablet_mode_controller()->SetEnabledForTest(enable);
 }
 

ash/system/overview/overview_button_tray.cc

@@ -77,16 +77,15 @@ void OverviewButtonTray::UpdateIconVisibility() {
   // a modal dialog is present.
   SessionControllerImpl* session_controller =
       Shell::Get()->session_controller();
-
-  bool kiosk_next = Shell::Get()->kiosk_next_shell_controller()->IsEnabled();
-  bool events_blocked = Shell::Get()
-                            ->tablet_mode_controller()
-                            ->AreInternalInputDeviceEventsBlocked();
   bool active_session = session_controller->GetSessionState() ==
                         session_manager::SessionState::ACTIVE;
   bool app_mode = session_controller->IsRunningInAppMode();
 
-  SetVisible(!kiosk_next && events_blocked && active_session && !app_mode);
+  bool kiosk_next = Shell::Get()->kiosk_next_shell_controller()->IsEnabled();
+  bool should_show =
+      Shell::Get()->tablet_mode_controller()->ShouldShowOverviewButton();
+
+  SetVisible(should_show && active_session && !app_mode && !kiosk_next);
 }
 
 void OverviewButtonTray::OnGestureEvent(ui::GestureEvent* event) {

ash/test/ash_test_base.cc

@@ -30,6 +30,7 @@
 #include "ash/test_shell_delegate.h"
 #include "ash/utility/screenshot_controller.h"
 #include "ash/window_factory.h"
+#include "ash/wm/tablet_mode/tablet_mode_controller.h"
 #include "ash/wm/window_positioner.h"
 #include "ash/wm/work_area_insets.h"
 #include "base/memory/ptr_util.h"
@@ -157,6 +158,8 @@ void AshTestBase::SetUp() {
 
 void AshTestBase::TearDown() {
   teardown_called_ = true;
+  // Make sure that we can exit tablet mode before shutdown correctly.
+  Shell::Get()->tablet_mode_controller()->SetEnabledForTest(false);
   Shell::Get()->session_controller()->NotifyChromeTerminating();
 
   // Flush the message loop to finish pending release tasks.

ash/wm/tablet_mode/tablet_mode_controller.h

@@ -172,6 +172,24 @@ class ASH_EXPORT TabletModeController
     ++tab_drag_in_splitview_count_;
   }
 
+  // Enable/disable the tablet mode for development. Please see cc file
+  // for more details.
+  void SetEnabledForDev(bool enabled);
+
+  // Returns true if the system tray should have a overview button.
+  bool ShouldShowOverviewButton() const;
+
+  // Defines how the tablet mode controller controls the
+  // tablet mode and its transition between clamshell mode.
+  // This is defined as a public to define constexpr in cc.
+  struct TabletModeBehavior {
+    bool use_sensor = true;
+    bool observe_display_events = true;
+    bool observe_external_pointer_device_events = true;
+    bool block_internal_input_device = false;
+    bool always_show_overview_button_in_tablet_mode = false;
+  };
+
  private:
   class TabletModeTransitionFpsCounter;
   friend class TabletModeControllerTestApi;
@@ -242,11 +260,6 @@ class ASH_EXPORT TabletModeController
   // otherwise returns TABLET_MODE_INTERNAL_INACTIVE.
   TabletModeIntervalType CurrentTabletModeIntervalType();
 
-  // Checks whether we want to allow change the current ui mode to tablet mode
-  // or clamshell mode. This returns false if the user set a flag for the
-  // software to behave in a certain way regardless of configuration.
-  bool AllowUiModeChange() const;
-
   // Called when a pointing device config is changed, or when a device list is
   // sent from device manager. This will exit tablet mode if needed.
   void HandlePointingDeviceAddedOrRemoved();
@@ -364,9 +377,6 @@ class ASH_EXPORT TabletModeController
   // mode.
   TabletModeToggleObserver* toggle_observer_ = nullptr;
 
-  // Tracks whether a flag is used to force ui mode.
-  UiMode force_ui_mode_ = UiMode::kNone;
-
   State state_ = State::kInClamshellMode;
 
   // Calls RecordLidAngle() periodically.
@@ -404,6 +414,8 @@ class ASH_EXPORT TabletModeController
 
   base::ObserverList<TabletModeObserver>::Unchecked tablet_mode_observers_;
 
+  TabletModeBehavior tablet_mode_behavior_;
+
   base::WeakPtrFactory<TabletModeController> weak_factory_{this};
 
   DISALLOW_COPY_AND_ASSIGN(TabletModeController);

ash/wm/tablet_mode/tablet_mode_controller_test_api.cc

@@ -18,11 +18,11 @@ TabletModeControllerTestApi::TabletModeControllerTestApi()
 TabletModeControllerTestApi::~TabletModeControllerTestApi() = default;
 
 void TabletModeControllerTestApi::EnterTabletMode() {
-  tablet_mode_controller_->AttemptEnterTabletMode();
+  tablet_mode_controller_->SetEnabledForTest(true);
 }
 
 void TabletModeControllerTestApi::LeaveTabletMode() {
-  tablet_mode_controller_->AttemptLeaveTabletMode();
+  tablet_mode_controller_->SetEnabledForTest(false);
 }
 
 void TabletModeControllerTestApi::AttachExternalMouse() {