Record Stability.IOS.UTE.AppWillTerminateWasCalledInForeground

This metric will be recorded if applicationWillTerminate is called after
applicationWillEnterForegroud. In that case the app will not properly
mark the clean exit.

Bug: 1167418
Change-Id: I0fa90862b18cc925b523d71d15fbf7af5c3b0e74
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2633974
Commit-Queue: Eugene But <eugenebut@chromium.org>
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Reviewed-by: Jesse Doherty <jwd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844941}

ios/chrome/app/application_delegate/app_state.mm

@@ -426,6 +426,10 @@ initWithBrowserLauncher:(id<BrowserLauncher>)browserLauncher
 }
 
 - (void)applicationWillTerminate:(UIApplication*)application {
+  if (!_applicationInBackground) {
+    base::UmaHistogramBoolean(
+        "Stability.IOS.UTE.AppWillTerminateWasCalledInForeground", true);
+  }
   if (_appIsTerminating) {
     // Previous handling of this method spun the runloop, resulting in
     // recursive calls; this does not appear to happen with the new shutdown

tools/metrics/histograms/histograms_xml/stability/histograms.xml

@@ -387,6 +387,17 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </token>
 </histogram>
 
+<histogram name="Stability.IOS.UTE.AppWillTerminateWasCalledInForeground"
+    enum="Boolean" expires_after="2021-06-06">
+  <owner>olivierrobin@chromium.org</owner>
+  <owner>eugenebut@google.com</owner>
+  <summary>
+    Recorded on iOS when applicationWillTerminate callback is called when app is
+    in the foreground. When this happens the app will not write clean exit
+    beacon and shutdown will not be clean.
+  </summary>
+</histogram>
+
 <histogram name="Stability.iOS.UTE.AvailableStorage" units="KB"
     expires_after="2021-06-06">
   <owner>michaeldo@chromium.org</owner>