[Chromeshine] Add usage stats consent activity and pref

This change enables users to consent to sharing their browsing data with
Digital Wellbeing. UsageStatsConsentActivity and UsageStatsPromoDialog
are the relevant piece of UI code for this. The user's choice is stored in a
new pref, whose value is readable and writeable via methods added to
UsageStatsBridge.

This change also stops gating usage stats compilation on enable_usage_stats.
This flag isn't actually needed; pre-q builds succeed without it. The only
thing preventing me from removing it is that clank code references it.

in a follow-up

Bug: 902490
Change-Id: Ic57c8a8624fd90b608c07e52bbe6f946c3780105
Binary-Size: Compiling in an entire feature, working on further mitigation
Reviewed-on: https://chromium-review.googlesource.com/c/1403925
Reviewed-by: Gabriel Charette <[email protected]>
Reviewed-by: agrieve <[email protected]>
Reviewed-by: Theresa <[email protected]>
Reviewed-by: Filip Gorski <[email protected]>
Commit-Queue: Patrick Noland <[email protected]>
Cr-Commit-Position: refs/heads/master@{#623085}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 5d57bb1..29ebdd1 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -195,6 +195,7 @@
 #include "chrome/browser/android/ntp/recent_tabs_page_prefs.h"
 #include "chrome/browser/android/oom_intervention/oom_intervention_decider.h"
 #include "chrome/browser/android/preferences/browser_prefs_android.h"
+#include "chrome/browser/android/usage_stats/usage_stats_bridge.h"
 #include "chrome/browser/geolocation/geolocation_permission_context_android.h"
 #include "chrome/browser/ntp_snippets/download_suggestions_provider.h"
 #include "components/cdm/browser/media_drm_storage_impl.h"
@@ -663,6 +664,7 @@
   GeolocationPermissionContextAndroid::RegisterProfilePrefs(registry);
   PartnerBookmarksShim::RegisterProfilePrefs(registry);
   RecentTabsPagePrefs::RegisterProfilePrefs(registry);
+  usage_stats::UsageStatsBridge::RegisterProfilePrefs(registry);
 #if BUILDFLAG(ENABLE_FEED_IN_CHROME)
   feed::FeedSchedulerHost::RegisterProfilePrefs(registry);
   feed::RefreshThrottler::RegisterProfilePrefs(registry);