Moving/renaming webrtc/common.h.

This file defines webrtc::Config which was mostly used by modules/audio_processing. The files webrtc/common.h, webrtc/common.cc and webrtc/test/common_unittests.cc are moved to modules/audio_processing and the few remaining uses of webrtc::Config are replaced with simpler code.

- For NetEq and pacing configuration, a VoEBase::ChannelConfig is passed to VoEBase::CreateChannel().
- Removes the need for VoiceEngine::Create(const Config& config). No need to store the webrtc::Config in VoE shared state.

BUG=webrtc:5879

Review-Url: https://codereview.webrtc.org/2307533004
Cr-Original-Commit-Position: refs/heads/master@{#14109}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 88499ecaca050be2dd21fff17140d6681c3bac95
diff --git a/test/call_test.cc b/test/call_test.cc
index a766f79..e81d947 100644
--- a/test/call_test.cc
+++ b/test/call_test.cc
@@ -8,7 +8,6 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include "webrtc/base/checks.h"
-#include "webrtc/common.h"
 #include "webrtc/config.h"
 #include "webrtc/modules/audio_coding/codecs/builtin_audio_decoder_factory.h"
 #include "webrtc/test/call_test.h"
@@ -312,9 +311,9 @@
   voe_send_.codec = VoECodec::GetInterface(voe_send_.voice_engine);
   EXPECT_EQ(0, voe_send_.base->Init(fake_send_audio_device_.get(), nullptr,
                                     decoder_factory_));
-  Config voe_config;
-  voe_config.Set<VoicePacing>(new VoicePacing(true));
-  voe_send_.channel_id = voe_send_.base->CreateChannel(voe_config);
+  VoEBase::ChannelConfig config;
+  config.enable_voice_pacing = true;
+  voe_send_.channel_id = voe_send_.base->CreateChannel(config);
   EXPECT_GE(voe_send_.channel_id, 0);
 
   voe_recv_.voice_engine = VoiceEngine::Create();