Do not notify Volume change event to CrasAudioHandler::Observer when CrasAudioHandler change volume…

chromeos/audio/cras_audio_handler.cc

 // Copyright (c) 2013 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 "chromeos/audio/cras_audio_handler.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 593 matching lines @@
     return;
   }
 
   // Sync internal volume state and notify UI for the change. We trust cras
   // signal to report the volume state of the device, no matter which source
   // set the volume, i.e., volume could be set from non-chrome source, like
   // Bluetooth headset, etc. Assume all active output devices share a single
   // volume.
   output_volume_ = volume;
   audio_pref_handler_->SetVolumeGainValue(*device, volume);
+
+  if (initializing_audio_state_) {
+    // Reset the flag after the first OutputNodeVolumeChanged, just in case
+    // cras didn't respond to the initial SetOutputNodeVolume request.
+    initializing_audio_state_ = false;
+    // Do not notify the observers for volume changed event if CrasAudioHandler
+    // is initializing its state, i.e., the volume change event is not from
+    // user action, no need to notify UI to pop uo the volume slider bar.
+    if (init_node_id_ == node_id && init_volume_ ==  volume)
+      return;
+  }
+
   FOR_EACH_OBSERVER(AudioObserver, observers_,
                     OnOutputNodeVolumeChanged(node_id, volume));
 }
 
 void CrasAudioHandler::ActiveOutputNodeChanged(uint64_t node_id) {
   if (active_output_node_id_ == node_id)
     return;
 
   // Active audio output device should always be changed by chrome.
   // During system boot, cras may change active input to unknown device 0x1,
@@ skipping 85 matching lines @@
   // Mute the output during HDMI re-discovering grace period.
   if (hdmi_rediscovering_ && !IsHDMIPrimaryOutputDevice()) {
     VLOG(1) << "Mute the output during HDMI re-discovering grace period";
     output_mute_on_ = true;
   } else {
     output_mute_on_ = audio_pref_handler_->GetMuteValue(*device);
   }
   output_volume_ = audio_pref_handler_->GetOutputVolumeValue(device);
 
   SetOutputMuteInternal(output_mute_on_);
+
+  if (initializing_audio_state_) {
+    init_node_id_ = active_output_node_id_;
+    init_volume_ = output_volume_;
+  }
   SetOutputNodeVolume(active_output_node_id_, output_volume_);
 }
 
 // This sets up the state of an additional active node.
 void CrasAudioHandler::SetupAdditionalActiveAudioNodeState(uint64_t node_id) {
   const AudioDevice* device = GetDeviceFromId(node_id);
   if (!device) {
     VLOG(1) << "Can't set up audio state for unknown device id ="
             << "0x" << std::hex << node_id;
     return;
   }
 
   DCHECK(node_id != active_output_node_id_ && node_id != active_input_node_id_);
 
   // Note: The mute state is a system wide state, we don't set mute per device,
   // but just keep the mute state consistent for the active node in prefs.
   // The output volume should be set to the same value for all active output
   // devices. For input devices, we don't restore their gain value so far.
   // TODO(jennyz): crbug.com/417418, track the status for the decison if
   // we should persist input gain value in prefs.
   if (!device->is_input) {
     audio_pref_handler_->SetMuteValue(*device, IsOutputMuted());
     SetOutputNodeVolumePercent(node_id, GetOutputVolumePercent());
   }
 }
 
 void CrasAudioHandler::InitializeAudioState() {
+  initializing_audio_state_ = true;
   ApplyAudioPolicy();
 
   // Defer querying cras for GetNodes until cras service becomes available.
   cras_service_available_ = false;
   chromeos::DBusThreadManager::Get()
       ->GetCrasAudioClient()
       ->WaitForServiceToBeAvailable(base::Bind(
           &CrasAudioHandler::InitializeAudioAfterCrasServiceAvailable,
           weak_ptr_factory_.GetWeakPtr()));
 }
@@ skipping 572 matching lines @@
                      hdmi_rediscover_grace_period_duration_in_ms_),
       this, &CrasAudioHandler::UpdateAudioAfterHDMIRediscoverGracePeriod);
 }
 
 void CrasAudioHandler::SetHDMIRediscoverGracePeriodForTesting(
     int duration_in_ms) {
   hdmi_rediscover_grace_period_duration_in_ms_ = duration_in_ms;
 }
 
 }  // namespace chromeos