[Siri Shortcuts] Add metric for Siri Shortcuts count

Adds a metric to record the number of Chrome Siri Shortcuts the user has
created in the Siri Shortcuts app. This is recorded once at startup, as
a delayed startup task on the IO thread (to avoid hangs while querying
iOS for the list of shortcuts).

Bug: 935211
Change-Id: I70766050ba7faf5fb343e3515c98ff6ddca98bd6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2429306
Commit-Queue: Guillaume Jenkins <gujen@google.com>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Reviewed-by: Jesse Doherty <jwd@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813030}

ios/chrome/app/main_controller.mm

@@ -138,6 +138,9 @@ NSString* const kDeleteDownloads = @"DeleteDownloads";
 // Constants for deferred deletion of leftover temporary passwords files.
 NSString* const kDeleteTempPasswords = @"DeleteTempPasswords";
 
+// Constants for deferred UMA logging of existing Siri User shortcuts.
+NSString* const kLogSiriShortcuts = @"LogSiriShortcuts";
+
 // Constants for deferred sending of queued feedback.
 NSString* const kSendQueuedFeedback = @"SendQueuedFeedback";
 
@@ -984,6 +987,7 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
   [self scheduleSpotlightResync];
   [self scheduleDeleteTempDownloadsDirectory];
   [self scheduleDeleteTempPasswordsDirectory];
+  [self scheduleLogSiriShortcuts];
   [self scheduleStartupAttemptReset];
   [self startFreeMemoryMonitoring];
   [self scheduleAppDistributionPings];
@@ -1020,6 +1024,15 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
                   }];
 }
 
+- (void)scheduleLogSiriShortcuts {
+  __weak StartupTasks* startupTasks = _startupTasks;
+  [[DeferredInitializationRunner sharedInstance]
+      enqueueBlockNamed:kLogSiriShortcuts
+                  block:^{
+                    [startupTasks logSiriShortcuts];
+                  }];
+}
+
 - (void)scheduleSpotlightResync {
   if (!_spotlightManager) {
     return;

ios/chrome/app/startup_tasks.h

@@ -20,6 +20,8 @@ class ChromeBrowserState;
 - (void)initializeOmaha;
 // Registers to receive UIApplicationWillResignActiveNotification.
 - (void)registerForApplicationWillResignActiveNotification;
+// Logs the number of Chrome Siri Shortcuts to UMA.
+- (void)logSiriShortcuts;
 
 @end
 

ios/chrome/app/startup_tasks.mm

@@ -7,6 +7,8 @@
 #import <MediaPlayer/MediaPlayer.h>
 
 #include "base/bind.h"
+#include "base/metrics/histogram_functions.h"
+#include "base/task/post_task.h"
 #import "ios/chrome/app/deferred_initialization_runner.h"
 #include "ios/chrome/app/intents/SearchInChromeIntent.h"
 #include "ios/chrome/browser/application_context.h"
@@ -77,6 +79,26 @@ NSString* const kStartProfileStartupTaskRunners =
            object:nil];
 }
 
+- (void)logSiriShortcuts {
+  base::ThreadPool::PostTask(
+      FROM_HERE, {base::MayBlock(), base::TaskPriority::BEST_EFFORT},
+      base::BindOnce(^{
+        [[INVoiceShortcutCenter sharedCenter]
+            getAllVoiceShortcutsWithCompletion:^(
+                NSArray<INVoiceShortcut*>* voiceShortcuts, NSError* error) {
+              if (error || !voiceShortcuts) {
+                return;
+              }
+
+              // The 20 shortcuts cap is arbitrary but seems like a reasonable
+              // limit.
+              base::UmaHistogramExactLinear(
+                  "IOS.SiriShortcuts.Count",
+                  base::saturated_cast<int>([voiceShortcuts count]), 20);
+            }];
+      }));
+}
+
 #pragma mark - Private methods.
 
 + (void)performDeferredInitializationForBrowserState:

tools/metrics/histograms/histograms_xml/ios/histograms.xml

@@ -700,6 +700,22 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="IOS.SiriShortcuts.Count" units="shortcuts"
+    expires_after="2021-02-28">
+  <owner>gujen@google.com</owner>
+  <owner>sebsg@chromium.org</owner>
+  <summary>
+    Counts the number of Chrome Siri Shortcuts that the user has created in the
+    Siri Shortcuts app. This is recorded once during startup. The histogram caps
+    at 20 shortcuts, which is an arbitrary but reasonable limit. Note that
+    shortcuts that have multiple actions are not counted if at least one action
+    isn't a Chrome-provided one. For example, a shortcut that opens URLs in
+    Chrome and then opens URLs in another app won't be counted. As such, this
+    metric undercounts the true number of Chrome shortcuts. This is a
+    restriction of the native Shortcuts API.
+  </summary>
+</histogram>
+
 <histogram name="IOS.Spotlight.Action" enum="IOSSpotlightAction"
     expires_after="2021-02-28">
   <owner>eugenebut@chromium.org</owner>