chromeos: Ignore power button presses when screen is off.

Make PowerButtonController ignore power button events when
the screen is turned off -- if the user hits the power
button to turn the screen back on, we don't want to lock or
shutdown if they hold it a bit too long.

BUG=128451
TEST=added, also did manual testing


Review URL: https://chromiumcodereview.appspot.com/10382211

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@137679 0039d316-1c4b-4281-b951-d872f2087c98

ash/wm/power_button_controller.cc

@@ -285,6 +285,7 @@ PowerButtonController::PowerButtonController()
       unlocked_login_status_(user::LOGGED_IN_NONE),
       power_button_down_(false),
       lock_button_down_(false),
+      screen_is_off_(false),
       shutting_down_(false),
       has_legacy_power_button_(
           CommandLine::ForCurrentProcess()->HasSwitch(
@@ -345,6 +346,10 @@ void PowerButtonController::OnLockStateChanged(bool locked) {
   }
 }
 
+void PowerButtonController::OnScreenBrightnessChanged(double percent) {
+  screen_is_off_ = percent <= 0.001;
+}
+
 void PowerButtonController::OnStartingLock() {
   if (shutting_down_ || login_status_ == user::LOGGED_IN_LOCKED)
     return;
@@ -368,6 +373,11 @@ void PowerButtonController::OnPowerButtonEvent(
   if (shutting_down_)
     return;
 
+  // Avoid starting the lock/shutdown sequence if the power button is pressed
+  // while the screen is off (http://crbug.com/128451).
+  if (screen_is_off_)
+    return;
+
   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

ash/wm/power_button_controller.h

@@ -142,6 +142,9 @@ class ASH_EXPORT PowerButtonController : public aura::RootWindowObserver,
     has_legacy_power_button_ = legacy;
   }
 
+  // Called when the current screen brightness changes.
+  void OnScreenBrightnessChanged(double percent);
+
   // Called when Chrome gets a request to display the lock screen.
   void OnStartingLock();
 
@@ -203,6 +206,9 @@ class ASH_EXPORT PowerButtonController : public aura::RootWindowObserver,
   bool power_button_down_;
   bool lock_button_down_;
 
+  // Is the screen currently turned off?
+  bool screen_is_off_;
+
   // Are we in the process of shutting the machine down?
   bool shutting_down_;
 

ash/wm/power_button_controller_unittest.cc

@@ -539,5 +539,22 @@ TEST_F(PowerButtonControllerTest, ResizeBackgroundLayer) {
             test_api_->GetBackgroundLayerBounds().ToString());
 }
 
+// Test that we ignore power button presses when the screen is turned off.
+TEST_F(PowerButtonControllerTest, IgnorePowerButtonIfScreenIsOff) {
+  controller_->OnLoginStateChanged(user::LOGGED_IN_USER);
+
+  // When the screen brightness is at 0%, we shouldn't do anything in response
+  // to power button presses.
+  controller_->OnScreenBrightnessChanged(0.0);
+  controller_->OnPowerButtonEvent(true, base::TimeTicks::Now());
+  EXPECT_FALSE(test_api_->lock_timer_is_running());
+
+  // After increasing the brightness to 10%, we should start the timer like
+  // usual.
+  controller_->OnScreenBrightnessChanged(10.0);
+  controller_->OnPowerButtonEvent(true, base::TimeTicks::Now());
+  EXPECT_TRUE(test_api_->lock_timer_is_running());
+}
+
 }  // namespace test
 }  // namespace ash

chrome/browser/chromeos/power/brightness_observer.cc

@@ -4,6 +4,8 @@
 
 #include "chrome/browser/chromeos/power/brightness_observer.h"
 
+#include "ash/shell.h"
+#include "ash/wm/power_button_controller.h"
 #include "chrome/browser/extensions/system/system_api.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 
@@ -19,6 +21,8 @@ BrightnessObserver::~BrightnessObserver() {
 
 void BrightnessObserver::BrightnessChanged(int level, bool user_initiated) {
   extensions::DispatchBrightnessChangedEvent(level, user_initiated);
+  ash::Shell::GetInstance()->power_button_controller()->
+      OnScreenBrightnessChanged(static_cast<double>(level));
 }
 
 }  // namespace chromeos

chrome/browser/chromeos/power/brightness_observer.h

@@ -12,8 +12,8 @@
 
 namespace chromeos {
 
-// This observer displays a bubble at the bottom of the screen showing the
-// current brightness level whenever the user changes it.
+// This observer listens for changes to the screen brightness and notifies
+// extensions and ash::PowerButtonController about them.
 class BrightnessObserver : public PowerManagerClient::Observer {
  public:
   // This class registers/unregisters itself as an observer in ctor/dtor.