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

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index def9351f6f3b864b24008f8640a152bce4f382e6..18bba6ba459bc379c422083884d93bbb5db1e4fa 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -97250,6 +97250,7 @@ value.
   <int value="-535208779" label="enable-native-cups"/>
   <int value="-531810064" label="saveas-menu-label"/>
   <int value="-528927088" label="AutofillCreditCardPopupLayout:disabled"/>
+  <int value="-528149352" label="WebRtcUseEchoCanceller3:enabled"/>
   <int value="-519960638" label="enable-site-engagement-service"/>
   <int value="-518104091" label="NewAudioRenderingMixingStrategy:enabled"/>
   <int value="-516845951" label="enable-embedded-extension-options"/>
@@ -97643,6 +97644,7 @@ value.
   <int value="1220171692" label="SpeculativeLaunchServiceWorker:enabled"/>
   <int value="1220464509" label="enable-first-run-ui-transitions"/>
   <int value="1221559505" label="enable-spelling-feedback-field-trial"/>
+  <int value="1222017136" label="WebRtcUseEchoCanceller3:disabled"/>
   <int value="1235800887" label="V8Ignition:enabled"/>
   <int value="1237297772" label="no-pings"/>
   <int value="1242632259" label="ContentSuggestionsCategoryOrder:disabled"/>