Ambient EQ: Add flag to hide/show the UI

- Adds a flag to allow the AEQ UI toggle to be displayed
- UI only displays on devices that support AEQ

BUG=chromium:1021193
TEST=manual

Change-Id: Iaf3a4ef24ed2512cc7096adae40fcdacd7ac3cd5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1894163
Commit-Queue: Zentaro Kavanagh <[email protected]>
Reviewed-by: James Cook <[email protected]>
Cr-Commit-Position: refs/heads/master@{#714547}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 2745d67..62e8141 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -4124,6 +4124,10 @@
      FEATURE_VALUE_TYPE(features::kUseSkiaRenderer)},
 
 #if defined(OS_CHROMEOS)
+    {"allow-ambient-eq", flag_descriptions::kAllowAmbientEQName,
+     flag_descriptions::kAllowAmbientEQDescription, kOsCrOS,
+     FEATURE_VALUE_TYPE(ash::features::kAllowAmbientEQ)},
+
     {"allow-disable-mouse-acceleration",
      flag_descriptions::kAllowDisableMouseAccelerationName,
      flag_descriptions::kAllowDisableMouseAccelerationDescription, kOsCrOS,