[Android] Handle SyncDisabled policy for MOBILE_IDENTITY_CONSISTENCY

When SyncDisabled policy is set, show a toast saying that "Sync is
disabled by your administrator" when user taps on the sync row in main
settings page.

Screenshot: https://crbug.com/1136780#c3

Bug: 1136780
Change-Id: I9ba71843ecc191e1e4faaa24377bcaadbb6c07bd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2505749
Commit-Queue: Tanmoy Mollik <triploblastic@chromium.org>
Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822283}

chrome/android/java/src/org/chromium/chrome/browser/settings/MainSettings.java

@@ -4,6 +4,7 @@
 
 package org.chromium.chrome.browser.settings;
 
+import android.content.Context;
 import android.content.Intent;
 import android.os.Build;
 import android.os.Bundle;
@@ -345,12 +346,15 @@ public class MainSettings extends PreferenceFragmentCompat
         mManageSync.setIcon(SyncSettingsUtils.getSyncStatusIcon(getActivity()));
         mManageSync.setSummary(SyncSettingsUtils.getSyncStatusSummary(getActivity()));
         mManageSync.setOnPreferenceClickListener(pref -> {
-            if (isSyncConsentAvailable) {
+            Context context = getContext();
+            if (ProfileSyncService.get().isSyncDisabledByEnterprisePolicy()) {
+                SyncSettingsUtils.showSyncDisabledByAdministratorToast(context);
+            } else if (isSyncConsentAvailable) {
                 SettingsLauncher settingsLauncher = new SettingsLauncherImpl();
-                settingsLauncher.launchSettingsActivity(getContext(), ManageSyncSettings.class);
+                settingsLauncher.launchSettingsActivity(context, ManageSyncSettings.class);
             } else {
                 SigninActivityLauncherImpl.get().launchActivityForPromoDefaultFlow(
-                        getContext(), SigninAccessPoint.SETTINGS, primaryAccountName);
+                        context, SigninAccessPoint.SETTINGS, primaryAccountName);
             }
             return true;
         });

chrome/android/java/src/org/chromium/chrome/browser/sync/settings/SyncSettingsUtils.java

@@ -42,6 +42,7 @@ import org.chromium.components.signin.base.GoogleServiceAuthError;
 import org.chromium.components.sync.KeyRetrievalTriggerForUMA;
 import org.chromium.components.sync.StopSource;
 import org.chromium.ui.UiUtils;
+import org.chromium.ui.widget.Toast;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -426,4 +427,15 @@ public class SyncSettingsUtils {
                             Log.e(TAG, "Error opening key retrieval dialog: ", exception);
                         });
     }
+
+    /**
+     * Shows a toast indicating that sync is disabled for the account by the system administrator.
+     *
+     * @param context The context where the toast will be shown.
+     */
+    public static void showSyncDisabledByAdministratorToast(Context context) {
+        Toast.makeText(context, context.getString(R.string.sync_is_disabled_by_administrator),
+                     Toast.LENGTH_LONG)
+                .show();
+    }
 }