Remove VoEVolumeControl interface.

webrtc/voice_engine/BUILD.gn

Index: webrtc/voice_engine/BUILD.gn
diff --git a/webrtc/voice_engine/BUILD.gn b/webrtc/voice_engine/BUILD.gn
index 75f9a082c7b70255e578318812e8f3a4ab43d33b..2d40b2c72d4e23ab31251b5b84700441addb4280 100644
--- a/webrtc/voice_engine/BUILD.gn
+++ b/webrtc/voice_engine/BUILD.gn
@@ -83,7 +83,6 @@ rtc_static_library("voice_engine") {
     "include/voe_neteq_stats.h",
     "include/voe_network.h",
     "include/voe_rtp_rtcp.h",
-    "include/voe_volume_control.h",
     "monitor_module.h",
     "output_mixer.cc",
     "output_mixer.h",
@@ -113,8 +112,6 @@ rtc_static_library("voice_engine") {
     "voe_network_impl.h",
     "voe_rtp_rtcp_impl.cc",
     "voe_rtp_rtcp_impl.h",
-    "voe_volume_control_impl.cc",
-    "voe_volume_control_impl.h",
     "voice_engine_defines.h",
     "voice_engine_impl.cc",
     "voice_engine_impl.h",
@@ -293,7 +290,6 @@ if (rtc_include_tests) {
         "test/auto_test/standard/rtp_rtcp_extensions.cc",
         "test/auto_test/standard/rtp_rtcp_test.cc",
         "test/auto_test/standard/voe_base_misc_test.cc",
-        "test/auto_test/standard/volume_test.cc",
         "test/auto_test/voe_conference_test.cc",
         "test/auto_test/voe_standard_test.cc",
         "test/auto_test/voe_standard_test.h",