Making Chromoting use no GPO provider in PolicyLoaderWin.

The old Chromoting code (policy_hack before crrev.com/830193002) used to
always read Chromoting policies from the registry.  The new code (using
components/policy) ignores contents of the registry on non-domain-joined
machines.  This old-vs-new difference in behavior was unintentional.
The current changelist ensures that Chromoting's old behavior is preserved.

BUG=460734
TEST=1) components_unittests.exe, 2) remoting_unittests.exe, 3) remoting_unittests.exe --gtest_filter=*PolicyWatcher*Real* -v=1 copied and run from a non-domain-joined, test VM to verify that Chromoting gets its policies from the registry (HKLM\SOFTWARE\Policies\Google\Chrome) in this scenario.

Review URL: https://codereview.chromium.org/947353002

Cr-Commit-Position: refs/heads/master@{#317865}
(cherry picked from commit bccb49e)

TBR=dcaiafa

Review URL: https://codereview.chromium.org/959033002

Cr-Commit-Position: refs/branch-heads/2311@{#40}
Cr-Branched-From: 09b7de5-refs/heads/master@{#317474}

components/policy/core/common/policy_loader_win.cc

@@ -461,9 +461,10 @@ scoped_ptr<PolicyBundle> PolicyLoaderWin::Load() {
     // timeout on it more aggressively. For now, there's no justification for
     // the additional effort this would introduce.
 
-    if (is_enterprise || !ReadPolicyFromGPO(scope, &gpo_dict, &status)) {
-      VLOG_IF(1, !is_enterprise) << "Failed to read GPO files for " << scope
-                                 << " falling back to registry.";
+    bool is_registry_forced = is_enterprise || gpo_provider_ == nullptr;
+    if (is_registry_forced || !ReadPolicyFromGPO(scope, &gpo_dict, &status)) {
+      VLOG_IF(1, !is_registry_forced) << "Failed to read GPO files for "
+                                      << scope << " falling back to registry.";
       gpo_dict.ReadRegistry(kScopes[i].hive, chrome_policy_key_);
     }
 

components/policy/core/common/policy_loader_win.h

@@ -51,6 +51,9 @@ class POLICY_EXPORT PolicyLoaderWin
   // The PReg file name used by GPO.
   static const base::FilePath::CharType kPRegFileName[];
 
+  // Passing |gpo_provider| equal nullptr forces all reads to go through the
+  // registry.  This is undesirable for Chrome (see crbug.com/259236), but
+  // needed for some other use cases (i.e. Chromoting - see crbug.com/460734).
   PolicyLoaderWin(scoped_refptr<base::SequencedTaskRunner> task_runner,
                   const base::string16& chrome_policy_key,
                   AppliedGPOListProvider* gpo_provider);

components/policy/core/common/policy_loader_win_unittest.cc

@@ -712,6 +712,8 @@ class PolicyLoaderWinTest : public PolicyTestBase,
                                    .AppendASCII("data")
                                    .AppendASCII("policy")
                                    .AppendASCII("gpo");
+
+    gpo_list_provider_ = this;
   }
 
   // AppliedGPOListProvider:
@@ -740,7 +742,8 @@ class PolicyLoaderWinTest : public PolicyTestBase,
   }
 
   bool Matches(const PolicyBundle& expected) {
-    PolicyLoaderWin loader(loop_.message_loop_proxy(), kTestPolicyKey, this);
+    PolicyLoaderWin loader(loop_.message_loop_proxy(), kTestPolicyKey,
+                           gpo_list_provider_);
     scoped_ptr<PolicyBundle> loaded(
         loader.InitialLoad(schema_registry_.schema_map()));
     return loaded->Equals(expected);
@@ -783,6 +786,7 @@ class PolicyLoaderWinTest : public PolicyTestBase,
   PGROUP_POLICY_OBJECT gpo_list_;
   DWORD gpo_list_status_;
   base::FilePath test_data_dir_;
+  AppliedGPOListProvider* gpo_list_provider_;
 };
 
 const base::char16 PolicyLoaderWinTest::kTestPolicyKey[] =
@@ -1047,7 +1051,19 @@ TEST_F(PolicyLoaderWinTest, AppliedPolicyInDomain) {
   gpo_list_ = &gpo;
   gpo_list_status_ = ERROR_SUCCESS;
 
-  PolicyBundle empty;
+  EXPECT_TRUE(MatchesRegistrySentinel());
+}
+
+TEST_F(PolicyLoaderWinTest, GpoProviderNotSpecified) {
+  base::win::SetDomainStateForTesting(false);
+  InstallRegistrySentinel();
+  base::FilePath gpo_dir(test_data_dir_.AppendASCII("empty"));
+  GROUP_POLICY_OBJECT gpo;
+  InitGPO(&gpo, 0, gpo_dir, NULL, NULL);
+  gpo_list_ = &gpo;
+  gpo_list_status_ = ERROR_SUCCESS;
+  gpo_list_provider_ = nullptr;
+
   EXPECT_TRUE(MatchesRegistrySentinel());
 }
 

remoting/host/policy_watcher.cc

@@ -266,8 +266,9 @@ scoped_ptr<PolicyWatcher> PolicyWatcher::Create(
   // Chromium.
   scoped_ptr<policy::AsyncPolicyLoader> policy_loader;
 #if defined(OS_WIN)
-  policy_loader = policy::PolicyLoaderWin::Create(
-      file_task_runner, L"SOFTWARE\\Policies\\Google\\Chrome");
+  policy_loader.reset(new policy::PolicyLoaderWin(
+      file_task_runner, L"SOFTWARE\\Policies\\Google\\Chrome",
+      nullptr));  // nullptr = don't use GPO / always read from the registry.
 #elif defined(OS_MACOSX)
   CFStringRef bundle_id = CFSTR("com.google.Chrome");
   policy_loader.reset(new policy::PolicyLoaderMac(