Tablet-like power button behavior on Convertible/Tablet ChromeOS devices

ash/wm/power_button_controller.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/wm/power_button_controller.h"
 
 #include "ash/common/accelerators/accelerator_controller.h"
 #include "ash/common/ash_switches.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/system/audio/tray_audio.h"
 #include "ash/common/system/tray/system_tray.h"
 #include "ash/common/wm/maximize_mode/maximize_mode_controller.h"
 #include "ash/common/wm_shell.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/shell.h"
 #include "ash/wm/lock_state_controller.h"
 #include "ash/wm/session_state_animator.h"
 #include "base/command_line.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/display/types/display_snapshot.h"
-#include "ui/events/event_handler.h"

[Qiang(Joe) Xu, 2016/11/04 23:18:21]

it is included in head file.

 #include "ui/wm/core/compound_event_filter.h"
 
 #if defined(OS_CHROMEOS)
+#include "ash/wm/tablet_power_button_controller.h"
 #include "chromeos/audio/cras_audio_handler.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #endif
 
 namespace ash {
 
 PowerButtonController::PowerButtonController(LockStateController* controller)
     : power_button_down_(false),
       lock_button_down_(false),
       volume_down_pressed_(false),
 #if defined(OS_CHROMEOS)
       volume_percent_before_screenshot_(0),
 #endif
       brightness_is_zero_(false),
       internal_display_off_and_external_display_on_(false),
       has_legacy_power_button_(
           base::CommandLine::ForCurrentProcess()->HasSwitch(
               switches::kAuraLegacyPowerButton)),
 #if defined(OS_CHROMEOS)
       enable_quick_lock_(base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kAshEnableTouchView)),
 #else
       enable_quick_lock_(false),
 #endif
       controller_(controller) {
 #if defined(OS_CHROMEOS)
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->AddObserver(
       this);
+  tablet_controller_.reset(new TabletPowerButtonController(controller_));
   Shell::GetInstance()->display_configurator()->AddObserver(this);
 #endif
   Shell::GetInstance()->PrependPreTargetHandler(this);
 }
 
 PowerButtonController::~PowerButtonController() {
   Shell::GetInstance()->RemovePreTargetHandler(this);
 #if defined(OS_CHROMEOS)
   Shell::GetInstance()->display_configurator()->RemoveObserver(this);
+  tablet_controller_.reset();
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->RemoveObserver(
       this);
 #endif
 }
 
 void PowerButtonController::OnScreenBrightnessChanged(double percent) {
   brightness_is_zero_ = percent <= 0.001;
 }
 
 void PowerButtonController::OnPowerButtonEvent(
     bool down,
     const base::TimeTicks& timestamp) {
   power_button_down_ = down;
 
   if (controller_->ShutdownRequested())
     return;
 
+  bool should_take_screenshot = down && volume_down_pressed_ &&
+                                WmShell::Get()
+                                    ->maximize_mode_controller()
+                                    ->IsMaximizeModeWindowManagerEnabled();

[Qiang(Joe) Xu, 2016/11/04 23:18:21]

Shall we make IsTabletModeActive and IsTabletModeSupported methods belong to
PowerButtonController?

They can be static method so that TabletPowerButtonController can also call
them.

+
+#if defined(OS_CHROMEOS)
+  if (!has_legacy_power_button_ && !should_take_screenshot &&
+      tablet_controller_->ShouldHandlePowerButtonEvents()) {
+    tablet_controller_->OnPowerButtonEvent(down, timestamp,
+                                           brightness_is_zero_);
+    return;
+  }
+#endif
+
   // Avoid starting the lock/shutdown sequence if the power button is pressed
   // while the screen is off (http://crbug.com/128451), unless an external
   // display is still on (http://crosbug.com/p/24912).
   if (brightness_is_zero_ && !internal_display_off_and_external_display_on_)
     return;
 
-  if (volume_down_pressed_ && down &&
-      WmShell::Get()
-          ->maximize_mode_controller()
-          ->IsMaximizeModeWindowManagerEnabled()) {
+  if (should_take_screenshot) {
     SystemTray* system_tray = Shell::GetInstance()->GetPrimarySystemTray();
     if (system_tray && system_tray->GetTrayAudio())
       system_tray->GetTrayAudio()->HideDetailedView(false);
 
     WmShell::Get()->accelerator_controller()->PerformActionIfEnabled(
         TAKE_SCREENSHOT);
 
 #if defined(OS_CHROMEOS)
     // Restore volume.
     chromeos::CrasAudioHandler* audio_handler =
@@ skipping 23 matching lines @@
   } else {  // !has_legacy_power_button_
     if (down) {
       // If we already have a pending request to lock the screen, wait.
       if (controller_->LockRequested())
         return;
 
       if (session_state_delegate->CanLockScreen() &&
           !session_state_delegate->IsUserSessionBlocked()) {
         if (WmShell::Get()
                 ->maximize_mode_controller()
                 ->IsMaximizeModeWindowManagerEnabled() &&

[Qiang(Joe) Xu, 2016/11/04 23:18:21]

This should not be reached any more.. we probably need to delete the related
code. I am surprised to see no tests are broken here. Deletion of code can be
the separate cl I think.

             enable_quick_lock_)
           controller_->StartLockAnimationAndLockImmediately(true);
         else
           controller_->StartLockAnimation(true);
       } else {
         controller_->StartShutdownAnimation();
       }
     } else {  // Button is up.
       if (controller_->CanCancelLockAnimation())
         controller_->CancelLockAnimation();
@@ skipping 58 matching lines @@
 }
 
 void PowerButtonController::PowerButtonEventReceived(
     bool down,
     const base::TimeTicks& timestamp) {
   OnPowerButtonEvent(down, timestamp);
 }
 #endif  // defined(OS_CHROMEOS)
 
 }  // namespace ash