[Metrics] Disable FamilyUserMetricsProvider

FamilyUserMetricsProvider currently causes a crash bug in guest mode.
Disable the feature flag and browser test while looking into a fix.

Bug: 1137352
Change-Id: Ia327e39754f2bd48c9e9bfec11e4b1e6d47c447a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2472263
Auto-Submit: Toby Huang <tobyhuang@chromium.org>
Reviewed-by: Aga Wronska <agawronska@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#817167}

chrome/browser/chromeos/child_accounts/family_features.cc

@@ -7,6 +7,6 @@
 namespace chromeos {
 
 const base::Feature kFamilyUserMetricsProvider{
-    "FamilyUserMetricsProvider", base::FEATURE_ENABLED_BY_DEFAULT};
+    "FamilyUserMetricsProvider", base::FEATURE_DISABLED_BY_DEFAULT};
 
 }  // namespace chromeos

chrome/browser/metrics/family_user_metrics_provider_browsertest.cc

@@ -87,7 +87,7 @@ class FamilyUserMetricsProviderTest
       /*use_local_policy_server=*/false};
 };
 
-IN_PROC_BROWSER_TEST_P(FamilyUserMetricsProviderTest, UserCategory) {
+IN_PROC_BROWSER_TEST_P(FamilyUserMetricsProviderTest, DISABLED_UserCategory) {
   base::HistogramTester histogram_tester;
   FamilyUserMetricsProvider provider;
   // Simulate calling ProvideCurrentSessionData() prior to logging in.