Expand ducking conditions

Update the IS_ANDROID_THINGS check to use the superset
IS_ANDROID_APPLIANCE, covering cases using other Android
platform builds.

Bug: b/156263192(internal)
Test: local build (device)
Change-Id: Ia750c8d31a98881e7efaa6e69b10f2f7a6ba0ab2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2298342
Reviewed-by: Luke Halliwell (slow) <halliwell@chromium.org>
Commit-Queue: Brett Kilty <brettk@google.com>
Cr-Commit-Position: refs/heads/master@{#788502}

chromecast/BUILD.gn

@@ -597,6 +597,7 @@ buildflag_header("chromecast_buildflags") {
     "ENABLE_PLAYREADY=$enable_playready",
     "ENABLE_VIDEO_CAPTURE_SERVICE=$enable_video_capture_service",
     "ENABLE_VOLUME_TABLES_ACCESS=$enable_volume_tables_access",
+    "IS_ANDROID_APPLIANCE=$is_android_appliance",
     "IS_ANDROID_THINGS=$is_android_things",
     "IS_ANDROID_THINGS_NON_PUBLIC=$is_android_things_non_public",
     "IS_CAST_AUDIO_ONLY=$is_cast_audio_only",

chromecast/browser/cast_web_view_default.cc

@@ -110,9 +110,9 @@ CastWebViewDefault::CastWebViewDefault(
   web_contents_->GetNativeView()->SetName(params.activity_id);
 #endif
 
-#if BUILDFLAG(IS_ANDROID_THINGS)
-  // Configure the ducking multiplier for AThings speakers. We don't want the
-  // Chromium MediaSession to duck since we are doing our own ducking.
+#if BUILDFLAG(IS_ANDROID_APPLIANCE)
+  // Configure the ducking multiplier for AThings-like speakers. We don't want
+  // the Chromium MediaSession to duck since we are doing our own ducking.
   constexpr double kDuckingMultiplier = 1.0;
   content::MediaSession::Get(web_contents_.get())
       ->SetDuckingVolumeMultiplier(kDuckingMultiplier);