Fix Volume slider is captured in screenshot done in touchview mode

ash/wm/power_button_controller.cc

Index: ash/wm/power_button_controller.cc
diff --git a/ash/wm/power_button_controller.cc b/ash/wm/power_button_controller.cc
index 73c686a403a69604803a88b1728c503c1bbe8d84..78cabbb0b23b3d4db252bc30a7f4e77955f9b01e 100644
--- a/ash/wm/power_button_controller.cc
+++ b/ash/wm/power_button_controller.cc
@@ -8,27 +8,37 @@
 #include "ash/common/ash_switches.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shell_window_ids.h"
+#include "ash/common/system/tray/system_tray_notifier.h"
 #include "ash/common/wm/maximize_mode/maximize_mode_controller.h"
 #include "ash/common/wm_shell.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 "base/task_runner.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/display/types/display_snapshot.h"
 #include "ui/events/event_handler.h"
 #include "ui/wm/core/compound_event_filter.h"
 
 #if defined(OS_CHROMEOS)
+#include "chromeos/audio/cras_audio_handler.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #endif
 
 namespace ash {
 
+namespace {
+const int kWaitVolumeSliderHiddenInMs = 200;
+}  // namespace
+
 PowerButtonController::PowerButtonController(LockStateController* controller)
     : power_button_down_(false),
       lock_button_down_(false),
       volume_down_pressed_(false),
+      first_pressed_volume_percent_(0),
+      volume_down_first_(false),
       brightness_is_zero_(false),
       internal_display_off_and_external_display_on_(false),
       has_legacy_power_button_(
@@ -80,8 +90,12 @@ void PowerButtonController::OnPowerButtonEvent(
       WmShell::Get()
           ->maximize_mode_controller()
           ->IsMaximizeModeWindowManagerEnabled()) {
-    WmShell::Get()->accelerator_controller()->PerformActionIfEnabled(
-        TAKE_SCREENSHOT);
+    WmShell::Get()->system_tray_notifier()->NotifyWillTakeScreenshot(
+        first_pressed_volume_percent_);
+    base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+        FROM_HERE, base::Bind(&PowerButtonController::TakingScreenshot,
+                              base::Unretained(this)),
+        base::TimeDelta::FromMilliseconds(kWaitVolumeSliderHiddenInMs));
     return;
   }
 
@@ -151,8 +165,24 @@ void PowerButtonController::OnLockButtonEvent(
 }
 
 void PowerButtonController::OnKeyEvent(ui::KeyEvent* event) {
-  if (event->key_code() == ui::VKEY_VOLUME_DOWN)
+  if (event->key_code() == ui::VKEY_VOLUME_DOWN) {
     volume_down_pressed_ = event->type() == ui::ET_KEY_PRESSED;
+#if defined(OS_CHROMEOS)
+    if (event->type() == ui::ET_KEY_RELEASED) {
+      volume_down_first_ = false;
+      return;
+    }
+    // We should avoid saving volume to |first_pressed_volume_percent_| if that
+    // is continuous press.
+    if (!volume_down_first_) {

[Daniel Erat, 2016/07/27 23:51:31]

can't you use event->is_repeat() to determine if this is a repeated event?

[Qiang(Joe) Xu, 2016/07/28 00:15:39]

Yes. Just find it. I will update it later.

+      chromeos::CrasAudioHandler* audio_handler =
+          chromeos::CrasAudioHandler::Get();
+      DCHECK(audio_handler->IsInitialized());
+      first_pressed_volume_percent_ = audio_handler->GetOutputVolumePercent();
+      volume_down_first_ = true;
+    }
+#endif
+  }
 }
 
 #if defined(OS_CHROMEOS)
@@ -179,4 +209,9 @@ void PowerButtonController::PowerButtonEventReceived(
 }
 #endif  // defined(OS_CHROMEOS)
 
+void PowerButtonController::TakingScreenshot() {
+  WmShell::Get()->accelerator_controller()->PerformActionIfEnabled(
+      TAKE_SCREENSHOT);
+}
+
 }  // namespace ash