[Chromecast] Implement new volume control API

chromecast/base/chromecast_switches.h

 // 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.
 
 #ifndef CHROMECAST_BASE_CHROMECAST_SWITCHES_H_
 #define CHROMECAST_BASE_CHROMECAST_SWITCHES_H_
 
 #include <string>
 
 #include "build/build_config.h"
@@ skipping 27 matching lines @@
 extern const char kAcceptResourceProvider[];
 
 // ALSA-based CMA switches. (Only valid for audio products.)
 extern const char kAlsaOutputBufferSize[];
 extern const char kAlsaOutputPeriodSize[];
 extern const char kAlsaOutputStartThreshold[];
 extern const char kAlsaOutputAvailMin[];
 extern const char kAlsaCheckCloseTimeout[];
 extern const char kAlsaEnableUpsampling[];
 extern const char kAlsaFixedOutputSampleRate[];
+extern const char kMaxOutputVolumeDba1m[];
 
 // Memory pressure switches
 extern const char kMemPressureSystemReservedKb[];
 
 // GPU process switches
 extern const char kCastInitialScreenWidth[];
 extern const char kCastInitialScreenHeight[];
 
 // Graphics switches
 extern const char kDesktopWindow1080p[];
 
 }  // namespace switches
 
 namespace chromecast {
 
 // Gets boolean value from switch |switch_string|.
 // --|switch_string| -> true
 // --|switch_string|="true" -> true
 // --|switch_string|="false" -> false
 // no switch named |switch_string| -> |default_value|
 bool GetSwitchValueBoolean(const std::string& switch_string,
                            const bool default_value);
 
+// Gets an integer value from switch |switch_name|. If the switch is not present
+// in the command line, or the value is not an integer, the |default_value| is
+// returned.
+int GetSwitchValueInt(const std::string& switch_name, const int default_value);
+
+// Gets a non-negative integer value from switch |switch_name|. If the switch is
+// not present in the command line, or the value is not a non-negative integer,
+// the |default_value| is returned.
+int GetSwitchValueNonNegativeInt(const std::string& switch_name,
+                                 const int default_value);
+
 }  // namespace chromecast
 
 #endif  // CHROMECAST_BASE_CHROMECAST_SWITCHES_H_