[Chromecast] Fake volume control for desktop build

Bug: internal b/80004505
Change-Id: I556e52aa344d0e6b93e642d8aa02e026566c161b
Reviewed-on: https://chromium-review.googlesource.com/1095983Reviewed-by: Stephen Lanham <slan@chromium.org>
Commit-Queue: Kenneth MacKay <kmackay@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566916}

chromecast/media/cma/backend/desktop/BUILD.gn

@@ -16,6 +16,7 @@ cast_source_set("desktop") {
     "media_sink_desktop.h",
     "video_decoder_desktop.cc",
     "video_decoder_desktop.h",
+    "volume_control_desktop.cc",
   ]
 
   deps = [

chromecast/media/cma/backend/desktop/volume_control_desktop.cc

+// Copyright 2018 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 "chromecast/public/volume_control.h"
+
+#include <string>
+#include <vector>
+
+namespace chromecast {
+namespace media {
+
+// static
+void VolumeControl::Initialize(const std::vector<std::string>& argv) {}
+
+// static
+void VolumeControl::Finalize() {}
+
+// static
+void VolumeControl::AddVolumeObserver(VolumeObserver* observer) {}
+
+// static
+void VolumeControl::RemoveVolumeObserver(VolumeObserver* observer) {}
+
+// static
+float VolumeControl::GetVolume(AudioContentType type) {
+  return 1.0f;
+}
+
+// static
+void VolumeControl::SetVolume(AudioContentType type, float level) {}
+
+// static
+bool VolumeControl::IsMuted(AudioContentType type) {
+  return false;
+}
+
+// static
+void VolumeControl::SetMuted(AudioContentType type, bool muted) {}
+
+// static
+void VolumeControl::SetOutputLimit(AudioContentType type, float limit) {}
+
+// static
+float VolumeControl::VolumeToDbFS(float volume) {
+  return 0.0f;
+}
+
+// static
+float VolumeControl::DbFSToVolume(float db) {
+  return 0.0f;
+}
+
+// static
+void VolumeControl::SetPowerSaveMode(bool power_save_on) {}
+
+}  // namespace media
+}  // namespace chromecast