Add usemojodecoder feature for IME extension

Bug: 888885
Change-Id: Ifa248fed62148cae3d3d8c5f1d2a382dcf48d3bd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1886082Reviewed-by: Darren Shen <shend@chromium.org>
Commit-Queue: Leo Zhang <googleo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710248}

chrome/browser/extensions/api/virtual_keyboard_private/chrome_virtual_keyboard_delegate.cc

@@ -376,6 +376,9 @@ void ChromeVirtualKeyboardDelegate::OnHasInputDevices(
   features->AppendString(GenerateFeatureFlag(
       "handwritinggesture",
       base::FeatureList::IsEnabled(features::kHandwritingGesture)));
+  features->AppendString(GenerateFeatureFlag(
+      "usemojodecoder", base::FeatureList::IsEnabled(
+                            chromeos::features::kImeDecoderWithSandbox)));
   features->AppendString(GenerateFeatureFlag(
       "hmminputlogic",
       base::FeatureList::IsEnabled(chromeos::features::kImeInputLogicHmm)));