Web MIDI: convert Android native API switch to a field trial

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 0b8814dcb5fa9038c933c872745555b49bd0dd77..1b6673c838be2c19a9fe24f6ef248e65102ba251 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -90478,6 +90478,7 @@ value.
   <int value="-898594349" label="ash-enable-stable-overview-order"/>
   <int value="-898005938" label="disable-pinch-virtual-viewport"/>
   <int value="-894214299" label="fill-on-account-select:enabled"/>
+  <int value="-891856063" label="MidiManagerAndroid:enabled"/>
   <int value="-885601782" label="enable-contextual-search"/>
   <int value="-876148583" label="ArcBootCompletedBroadcast:disabled"/>
   <int value="-867087281" label="enable-virtual-keyboard"/>
@@ -90730,6 +90731,7 @@ value.
       label="disable-gesture-requirement-for-media-playback"/>
   <int value="457881889" label="enable-autoplay-muted-videos"/>
   <int value="458410433" label="disable-views-rect-based-targeting"/>
+  <int value="460136092" label="MidiManagerAndroid:disabled"/>
   <int value="460475728" label="wake-on-wifi-packet"/>
   <int value="466248382" label="disable-push-api-background-mode"/>
   <int value="468959230"