Add support to Google Update wrappers for the "automatic updates only" group policy setting.

chrome/installer/util/google_update_settings_unittest.cc

Index: chrome/installer/util/google_update_settings_unittest.cc
===================================================================
--- chrome/installer/util/google_update_settings_unittest.cc	(revision 205261)
+++ chrome/installer/util/google_update_settings_unittest.cc	(working copy)
@@ -544,12 +544,22 @@
                                                      &is_overridden));
   EXPECT_FALSE(is_overridden);
 
-  // The default policy should be in force for bogus values.
   EXPECT_EQ(ERROR_SUCCESS,
             RegKey(HKEY_LOCAL_MACHINE, kGoogleUpdatePoliciesKey,
                    KEY_SET_VALUE).WriteValue(kGoogleUpdateUpdateDefault,
                                              static_cast<DWORD>(3)));
   is_overridden = true;
+  EXPECT_EQ(GoogleUpdateSettings::AUTO_UPDATES_ONLY,
+            GoogleUpdateSettings::GetAppUpdatePolicy(kTestProductGuid,
+                                                     &is_overridden));
+  EXPECT_FALSE(is_overridden);
+
+  // The default policy should be in force for bogus values.
+  EXPECT_EQ(ERROR_SUCCESS,
+            RegKey(HKEY_LOCAL_MACHINE, kGoogleUpdatePoliciesKey,
+                   KEY_SET_VALUE).WriteValue(kGoogleUpdateUpdateDefault,
+                                             static_cast<DWORD>(4)));
+  is_overridden = true;
   EXPECT_EQ(kDefaultUpdatePolicy,
             GoogleUpdateSettings::GetAppUpdatePolicy(kTestProductGuid,
                                                      &is_overridden));
@@ -599,11 +609,21 @@
                                                      &is_overridden));
   EXPECT_TRUE(is_overridden);
 
+  EXPECT_EQ(ERROR_SUCCESS,
+            RegKey(HKEY_LOCAL_MACHINE, kGoogleUpdatePoliciesKey,
+                   KEY_SET_VALUE).WriteValue(app_policy_value.c_str(),
+                                             static_cast<DWORD>(3)));
+  is_overridden = false;
+  EXPECT_EQ(GoogleUpdateSettings::AUTO_UPDATES_ONLY,
+            GoogleUpdateSettings::GetAppUpdatePolicy(kTestProductGuid,
+                                                     &is_overridden));
+  EXPECT_TRUE(is_overridden);
+
   // The default policy should be in force for bogus values.
   EXPECT_EQ(ERROR_SUCCESS,
             RegKey(HKEY_LOCAL_MACHINE, kGoogleUpdatePoliciesKey,
                    KEY_SET_VALUE).WriteValue(app_policy_value.c_str(),
-                                             static_cast<DWORD>(3)));
+                                             static_cast<DWORD>(4)));
   is_overridden = true;
   EXPECT_EQ(GoogleUpdateSettings::UPDATES_DISABLED,
             GoogleUpdateSettings::GetAppUpdatePolicy(kTestProductGuid,