Adding functionality for activating for the WebRTC EchoCanceller3 functionality in Chrome.

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 4fd3c68be996609d0ccc1711aa0591949014b47f..d09c5a46f44aaaf33575d92d8bd62f4de22671e6 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -749,6 +749,9 @@ const FeatureEntry kFeatureEntries[] = {
     {"enable-webrtc-stun-origin", IDS_FLAGS_WEBRTC_STUN_ORIGIN_NAME,
      IDS_FLAGS_WEBRTC_STUN_ORIGIN_DESCRIPTION, kOsAll,
      SINGLE_VALUE_TYPE(switches::kEnableWebRtcStunOrigin)},
+    {"WebRtcUseEchoCanceller3", IDS_FLAGS_WEBRTC_ECHO_CANCELLER_3_NAME,

[peah, 2017/02/15 13:24:24]

I'm not sure about whether the "name" of the flag should be
WebRtcUseEchoCanceller3? This is the name that ends up in chrome://flags.

All the other flags have names of the format "enable-<feature>" but if I use
something that is different from the name of the feature that the flag controls,
I cannot set this via commandline. Setting the feature via chrome://flags works
though.

By naming the feature, and the flag the same, I'm able to set the flag both via
command line and chrome://flags

Please let me know if this is how it is expected to be done, or whether I should
use some other naming!

+     IDS_FLAGS_WEBRTC_ECHO_CANCELLER_3_DESCRIPTION, kOsAll,
+     FEATURE_VALUE_TYPE(features::kWebRtcUseEchoCanceller3)},
 #endif  // ENABLE_WEBRTC
 #if defined(OS_ANDROID)
     {"enable-osk-overscroll", IDS_FLAGS_ENABLE_OSK_OVERSCROLL_NAME,