Reuse one UserPolicySigninService for Android and iOS.

chrome/chrome_browser.gypi

Index: chrome/chrome_browser.gypi
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index d99874b605b8200407993693bb05018a15b7cfbb..3004f9fc0c423640115359af999816596303f542 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -1494,14 +1494,12 @@
         'browser/policy/cloud/user_cloud_policy_manager_factory.h',
         'browser/policy/cloud/user_policy_signin_service.cc',
         'browser/policy/cloud/user_policy_signin_service.h',
-        'browser/policy/cloud/user_policy_signin_service_android.cc',
-        'browser/policy/cloud/user_policy_signin_service_android.h',
         'browser/policy/cloud/user_policy_signin_service_base.cc',
         'browser/policy/cloud/user_policy_signin_service_base.h',
         'browser/policy/cloud/user_policy_signin_service_factory.cc',
         'browser/policy/cloud/user_policy_signin_service_factory.h',
-        'browser/policy/cloud/user_policy_signin_service_ios.h',
-        'browser/policy/cloud/user_policy_signin_service_ios.mm',
+        'browser/policy/cloud/user_policy_signin_service_mobile.cc',
+        'browser/policy/cloud/user_policy_signin_service_mobile.h',
         'browser/policy/configuration_policy_handler_list_factory.cc',
         'browser/policy/configuration_policy_handler_list_factory.h',
         'browser/policy/device_management_service_configuration.cc',
@@ -2774,6 +2772,8 @@
               'sources!': [
                 'browser/policy/managed_bookmarks_policy_handler.cc',
                 'browser/policy/managed_bookmarks_policy_handler.h',
+                'browser/policy/cloud/user_policy_signin_service_mobile.cc',
+                'browser/policy/cloud/user_policy_signin_service_mobile.h',
               ],
             }],
             ['OS=="ios"', {
@@ -2796,8 +2796,8 @@
                 ['include', '^browser/policy/cloud/user_policy_signin_service_base.h'],
                 ['include', '^browser/policy/cloud/user_policy_signin_service_factory.cc'],
                 ['include', '^browser/policy/cloud/user_policy_signin_service_factory.h'],
-                ['include', '^browser/policy/cloud/user_policy_signin_service_ios.h'],
-                ['include', '^browser/policy/cloud/user_policy_signin_service_ios.mm'],
+                ['include', '^browser/policy/cloud/user_policy_signin_service_mobile.cc'],
+                ['include', '^browser/policy/cloud/user_policy_signin_service_mobile.h'],
                 ['include', '^browser/policy/configuration_policy_handler_list_factory.cc'],
                 ['include', '^browser/policy/configuration_policy_handler_list_factory.h'],
                 ['include', '^browser/policy/managed_bookmarks_policy_handler.cc'],
@@ -2962,6 +2962,8 @@
             'browser/policy/cloud/user_policy_signin_service_base.h',
             'browser/policy/cloud/user_policy_signin_service_factory.cc',
             'browser/policy/cloud/user_policy_signin_service_factory.h',
+            'browser/policy/cloud/user_policy_signin_service_mobile.cc',
+            'browser/policy/cloud/user_policy_signin_service_mobile.h',
             'browser/profiles/avatar_menu_desktop.cc',
             'browser/profiles/avatar_menu_actions_desktop.cc',
             'browser/profiles/avatar_menu_actions_desktop.h',