Enable WebAssembly SIMD for cast_shell

We need to enable WebAssembly SIMD for cast_shell to improve app
performance. This override will be removed when SIMD is enabled by
default in upstream Chrome (expected around M87-M88).

Bug: internal b/161486194
Test: on-device
Change-Id: I76848819bfc0aefe3372a595856938bc1136c5f9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2311656
Auto-Submit: Sergey Volk <servolk@chromium.org>
Commit-Queue: Luke Halliwell (slow) <halliwell@chromium.org>
Reviewed-by: Luke Halliwell (slow) <halliwell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#790683}

chromecast/browser/cast_content_browser_client.cc

@@ -160,6 +160,9 @@ CastContentBrowserClient::CastContentBrowserClient(
       cast_feature_list_creator_(cast_feature_list_creator) {
   cast_feature_list_creator_->SetExtraEnableFeatures({
     ::media::kInternalMediaSession, features::kNetworkServiceInProcess,
+        // TODO(b/161486194): Can be removed when it's enabled by default in
+        // Chrome.
+        features::kWebAssemblySimd,
 #if defined(OS_ANDROID) && BUILDFLAG(ENABLE_VIDEO_CAPTURE_SERVICE)
         features::kMojoVideoCapture,
 #endif