Added quick lock mechanism while in Touchview

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/ash_switches.h"
 #include "ash/session/session_state_delegate.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.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/chromeos/display_snapshot.h"
+#include "ui/events/event_handler.h"
 #include "ui/wm/core/compound_event_filter.h"
 
 namespace ash {
 
 PowerButtonController::PowerButtonController(
     LockStateController* controller)
     : power_button_down_(false),
       lock_button_down_(false),
+      volume_down_pressed_(false),
       brightness_is_zero_(false),
       internal_display_off_and_external_display_on_(false),
       has_legacy_power_button_(
           CommandLine::ForCurrentProcess()->HasSwitch(
               switches::kAuraLegacyPowerButton)),
       controller_(controller) {
 #if defined(OS_CHROMEOS)
   Shell::GetInstance()->display_configurator()->AddObserver(this);
+  Shell::GetInstance()->PrependPreTargetHandler(this);
 #endif
 }
 
 PowerButtonController::~PowerButtonController() {
 #if defined(OS_CHROMEOS)
   Shell::GetInstance()->display_configurator()->RemoveObserver(this);
+  Shell::GetInstance()->RemovePreTargetHandler(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;
 
   // 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) {
+    Shell::GetInstance()->accelerator_controller()->PerformAction(
+        ash::TAKE_SCREENSHOT, ui::Accelerator());
+    return;
+  }
+
   const SessionStateDelegate* session_state_delegate =
       Shell::GetInstance()->session_state_delegate();
   if (has_legacy_power_button_) {
     // If power button releases won't get reported correctly because we're not
     // running on official hardware, just lock the screen or shut down
     // immediately.
     if (down) {
       if (session_state_delegate->CanLockScreen() &&
           !session_state_delegate->IsScreenLocked() &&
           !controller_->LockRequested()) {
         controller_->StartLockAnimationAndLockImmediately();
       } else {
         controller_->RequestShutdown();
       }
     }
   } 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->IsScreenLocked()) {
-        controller_->StartLockAnimation(true);
+        controller_->StartLockAnimationAndLockImmediately();

[flackr, 2014/06/10 17:34:42]

Won't this affect the regular power button on a chromebook keyboard?

       } else {
         controller_->StartShutdownAnimation();
       }
     } else {  // Button is up.
       if (controller_->CanCancelLockAnimation())
         controller_->CancelLockAnimation();
       else if (controller_->CanCancelShutdownAnimation())
         controller_->CancelShutdownAnimation();
     }
   }
@@ skipping 17 matching lines @@
   // something completely stupid if that assumption changes later).
   if (power_button_down_)
     return;
 
   if (down)
     controller_->StartLockAnimation(false);
   else
     controller_->CancelLockAnimation();
 }
 
+void PowerButtonController::OnKeyEvent(ui::KeyEvent* event) {
+  if (event->key_code() == ui::VKEY_VOLUME_DOWN) {
+    volume_down_pressed_ = event->type() == ui::ET_KEY_PRESSED ||
+                           event->type() == ui::ET_TRANSLATED_KEY_PRESS;
+  }
+}
+
 #if defined(OS_CHROMEOS)
 void PowerButtonController::OnDisplayModeChanged(
     const ui::DisplayConfigurator::DisplayStateList& display_states) {
   bool internal_display_off = false;
   bool external_display_on = false;
   for (size_t i = 0; i < display_states.size(); ++i) {
     const ui::DisplayConfigurator::DisplayState& state = display_states[i];
     if (state.display->type() == ui::DISPLAY_CONNECTION_TYPE_INTERNAL) {
       if (!state.display->current_mode())
         internal_display_off = true;
     } else if (state.display->current_mode()) {
       external_display_on = true;
     }
   }
   internal_display_off_and_external_display_on_ =
       internal_display_off && external_display_on;
 }
 #endif
 
 }  // namespace ash