Add AAudio input flag for WebView

This CL adds a WebView UI flag to toggle the UseAAudioInput feature
flag.

Bug: 1494390
Change-Id: Ic5456e14c179ed8dece85c80467ccd8f107e711a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5078371
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Thomas Guilbert <tguilbert@chromium.org>
Auto-Submit: Thomas Guilbert <tguilbert@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1231671}

android_webview/java/src/org/chromium/android_webview/common/ProductionSupportedFlagList.java

@@ -754,6 +754,9 @@ public final class ProductionSupportedFlagList {
         Flag.baseFeature(
                 CcFeatures.USE_MAP_RECT_FOR_PIXEL_MOVEMENT,
                 "Enables the usage of MapRect for computing filter pixel movement."),
+        Flag.baseFeature(
+                "UseAAudioInput",
+                "Enables the use of AAudio for capturing audio input. (Android Q+ only)"),
         Flag.baseFeature("UseRustJsonParser"),
         Flag.baseFeature("V8FlushCodeBasedOnTime"),
         Flag.baseFeature("V8FlushCodeBasedOnTabVisibility"),