Fix Volume slider is captured in screenshot done in touchview mode

ash/common/system/audio/tray_audio.cc

 // Copyright 2014 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/common/system/audio/tray_audio.h"
 
 #include <cmath>
 #include <utility>
 
 #include "ash/common/ash_constants.h"
@@ skipping 27 matching lines @@
 #include "ui/views/layout/box_layout.h"
 #include "ui/views/view.h"
 
 namespace ash {
 
 TrayAudio::TrayAudio(SystemTray* system_tray,
                      std::unique_ptr<system::TrayAudioDelegate> audio_delegate)
     : TrayImageItem(system_tray, IDR_AURA_UBER_TRAY_VOLUME_MUTE, UMA_AUDIO),
       audio_delegate_(std::move(audio_delegate)),
       volume_view_(NULL),
-      pop_up_volume_view_(false) {
-  WmShell::Get()->system_tray_notifier()->AddAudioObserver(this);
+      pop_up_volume_view_(false),
+      hide_popup_(false) {
+  SystemTrayNotifier* notifier = WmShell::Get()->system_tray_notifier();
+  notifier->AddAudioObserver(this);
+  notifier->AddMaximizeModeScreenshotObserver(this);
   display::Screen::GetScreen()->AddObserver(this);
 }
 
 TrayAudio::~TrayAudio() {
   display::Screen::GetScreen()->RemoveObserver(this);
-  WmShell::Get()->system_tray_notifier()->RemoveAudioObserver(this);
+  SystemTrayNotifier* notifier = WmShell::Get()->system_tray_notifier();
+  notifier->RemoveMaximizeModeScreenshotObserver(this);
+  notifier->RemoveAudioObserver(this);
 }
 
 // static
 bool TrayAudio::ShowAudioDeviceMenu() {
 #if defined(OS_CHROMEOS)
   return true;
 #else
   return false;
 #endif
 }
@@ skipping 37 matching lines @@
       static_cast<float>(audio_delegate_->GetOutputVolumeLevel()) / 100.0f;
   if (tray_view())
     tray_view()->SetVisible(GetInitialVisibility());
 
   if (volume_view_) {
     volume_view_->SetVolumeLevel(percent);
     SetDetailedViewCloseDelay(kTrayPopupAutoCloseDelayInSeconds);
     return;
   }
   pop_up_volume_view_ = true;
-  PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
+  // When the OutputNodeVolumeChanged is caused by a volume restore after
+  // maximize mode screenshot, it should not cause UI popup.
+  if (!hide_popup_)
+    PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
+  else
+    hide_popup_ = false;

[Daniel Erat, 2016/07/28 04:45:00]

this approach (hiding the next popup) feels a bit race-prone. it seems like it'd
be cleaner if the audio handler instead notified observers about whether the
change was user-initiated (in which case the popup should be shown) or automated
(in which case it shouldn't).

[Qiang(Joe) Xu, 2016/07/28 20:25:02]

done by moving the logic to cras_audio_handler

 }
 
 void TrayAudio::OnOutputMuteChanged(bool /* mute_on */, bool system_adjust) {
   if (tray_view())
     tray_view()->SetVisible(GetInitialVisibility());
 
   if (volume_view_) {
     volume_view_->Update();
     SetDetailedViewCloseDelay(kTrayPopupAutoCloseDelayInSeconds);
   } else if (!system_adjust) {
     pop_up_volume_view_ = true;
     PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
   }
 }
 
 void TrayAudio::OnAudioNodesChanged() {
   Update();
 }
 
 void TrayAudio::OnActiveOutputNodeChanged() {
   Update();
 }
 
 void TrayAudio::OnActiveInputNodeChanged() {
   Update();
 }
 
+void TrayAudio::OnWillTakeScreenshotInMaximizeMode() {
+  HideDetailedView();
+  hide_popup_ = true;
+}
+
 void TrayAudio::ChangeInternalSpeakerChannelMode() {
   // Swap left/right channel only if it is in Yoga mode.
   system::TrayAudioDelegate::AudioChannelMode channel_mode =
       system::TrayAudioDelegate::NORMAL;
   if (display::Display::HasInternalDisplay()) {
     const DisplayInfo& display_info =
         WmShell::Get()->GetDisplayInfo(display::Display::InternalDisplayId());
     if (display_info.GetActiveRotation() == display::Display::ROTATE_180)
       channel_mode = system::TrayAudioDelegate::LEFT_RIGHT_SWAPPED;
   }
@@ skipping 26 matching lines @@
   if (tray_view())
     tray_view()->SetVisible(GetInitialVisibility());
   if (volume_view_) {
     volume_view_->SetVolumeLevel(
         static_cast<float>(audio_delegate_->GetOutputVolumeLevel()) / 100.0f);
     volume_view_->Update();
   }
 }
 
 }  // namespace ash