Using PolicyServiceWatcher instead of PolicyWatcherLinux/Win/Mac.

remoting/host/policy_hack/policy_service_watcher.cc

Index: remoting/host/policy_hack/policy_service_watcher.cc
diff --git a/remoting/host/policy_hack/policy_service_watcher.cc b/remoting/host/policy_hack/policy_service_watcher.cc
new file mode 100644
index 0000000000000000000000000000000000000000..957109f9213207a00018db93f424d02620f39579
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+++ b/remoting/host/policy_hack/policy_service_watcher.cc
@@ -0,0 +1,224 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/files/file_path.h"
+#include "base/single_thread_task_runner.h"
+#include "components/policy/core/common/async_policy_loader.h"
+#include "components/policy/core/common/async_policy_provider.h"
+#include "components/policy/core/common/policy_namespace.h"
+#include "components/policy/core/common/policy_service.h"
+#include "components/policy/core/common/policy_service_impl.h"
+#include "components/policy/core/common/schema.h"
+#include "components/policy/core/common/schema_registry.h"
+#include "policy/policy_constants.h"
+#include "remoting/host/policy_hack/policy_watcher.h"
+
+#if defined(OS_CHROMEOS)
+#include "content/public/browser/browser_thread.h"
+#elif defined(OS_WIN)
+#include "components/policy/core/common/policy_loader_win.h"
+#elif defined(OS_MACOSX)
+#include "components/policy/core/common/policy_loader_mac.h"
+#include "components/policy/core/common/preferences_mac.h"
+#elif defined(OS_POSIX) && !defined(OS_ANDROID)
+#include "components/policy/core/common/config_dir_policy_loader.h"
+#endif
+
+using namespace policy;
+
+namespace remoting {
+namespace policy_hack {
+
+bool GetManagedPrefsDir(base::FilePath* result);
+
+namespace {
+
+// PolicyServiceWatcher is a concrete implementation of PolicyWatcher that wraps
+// an instance of PolicyService.
+class PolicyServiceWatcher : public PolicyWatcher,
+                             public PolicyService::Observer {
+ public:
+  // Constructor for the case when |policy_service| is borrowed.
+  //
+  // |policy_service_task_runner| is the task runner where it is safe
+  // to call |policy_service| methods and where we expect to get callbacks
+  // from |policy_service|.
+  PolicyServiceWatcher(const scoped_refptr<base::SingleThreadTaskRunner>&
+                           policy_service_task_runner,
+                       PolicyService* policy_service);
+
+  // Constructor for the case when |policy_service| is owned (and uses also
+  // owned |owned_policy_provider| and |owned_schema_registry|.
+  //
+  // |policy_service_task_runner| is the task runner where it is safe
+  // to call |policy_service| methods and where we expect to get callbacks
+  // from |policy_service|.
+  PolicyServiceWatcher(
+      const scoped_refptr<base::SingleThreadTaskRunner>&
+          policy_service_task_runner,
+      scoped_ptr<PolicyService> owned_policy_service,
+      scoped_ptr<ConfigurationPolicyProvider> owned_policy_provider,
+      scoped_ptr<SchemaRegistry> owned_schema_registry);
+
+  ~PolicyServiceWatcher() override;
+
+  // PolicyService::Observer interface.
+  void OnPolicyUpdated(const PolicyNamespace& ns,
+                       const PolicyMap& previous,
+                       const PolicyMap& current) override;
+  void OnPolicyServiceInitialized(PolicyDomain domain) override;
+
+  static PolicyNamespace GetPolicyNamespace() {
+    return PolicyNamespace(POLICY_DOMAIN_CHROME, std::string());
+  }
+
+ protected:
+  // PolicyWatcher interface.
+  void StartWatchingInternal() override;
+  void StopWatchingInternal() override;
+
+ private:
+  PolicyService* policy_service_;
+
+  // Order of fields below is important to ensure destruction takes object
+  // dependencies into account:
+  // - |owned_policy_service_| uses |owned_policy_provider_|
+  // - |owned_policy_provider_| uses |owned_schema_registry_|
+  scoped_ptr<SchemaRegistry> owned_schema_registry_;
+  scoped_ptr<ConfigurationPolicyProvider> owned_policy_provider_;
+  scoped_ptr<PolicyService> owned_policy_service_;
+
+  DISALLOW_COPY_AND_ASSIGN(PolicyServiceWatcher);
+};
+
+PolicyServiceWatcher::PolicyServiceWatcher(
+    const scoped_refptr<base::SingleThreadTaskRunner>&
+        policy_service_task_runner,
+    PolicyService* policy_service)
+    : PolicyWatcher(policy_service_task_runner) {
+  policy_service_ = policy_service;
+}
+
+PolicyServiceWatcher::PolicyServiceWatcher(
+    const scoped_refptr<base::SingleThreadTaskRunner>&
+        policy_service_task_runner,
+    scoped_ptr<PolicyService> owned_policy_service,
+    scoped_ptr<ConfigurationPolicyProvider> owned_policy_provider,
+    scoped_ptr<SchemaRegistry> owned_schema_registry)
+    : PolicyWatcher(policy_service_task_runner),
+      owned_schema_registry_(owned_schema_registry.Pass()),
+      owned_policy_provider_(owned_policy_provider.Pass()),
+      owned_policy_service_(owned_policy_service.Pass()) {
+  policy_service_ = owned_policy_service_.get();
+}
+
+PolicyServiceWatcher::~PolicyServiceWatcher() {
+  if (owned_policy_provider_) {
+    owned_policy_provider_->Shutdown();
+  }
+}
+
+void PolicyServiceWatcher::OnPolicyUpdated(const PolicyNamespace& ns,
+                                           const PolicyMap& previous,
+                                           const PolicyMap& current) {
+  scoped_ptr<base::DictionaryValue> policy_dict(new base::DictionaryValue());
+  for (PolicyMap::const_iterator it = current.begin(); it != current.end();
+       it++) {
+    // TODO(lukasza): Use policy::Schema::Normalize for schema verification.
+    policy_dict->Set(it->first, it->second.value->DeepCopy());
+  }
+  UpdatePolicies(policy_dict.get());
+}
+
+void PolicyServiceWatcher::OnPolicyServiceInitialized(PolicyDomain domain) {
+  PolicyNamespace ns = GetPolicyNamespace();
+  const PolicyMap& current = policy_service_->GetPolicies(ns);
+  OnPolicyUpdated(ns, current, current);
+}
+
+void PolicyServiceWatcher::StartWatchingInternal() {
+  // Listen for future policy changes.
+  policy_service_->AddObserver(POLICY_DOMAIN_CHROME, this);
+
+  // Process current policy state.
+  if (policy_service_->IsInitializationComplete(POLICY_DOMAIN_CHROME)) {
+    OnPolicyServiceInitialized(POLICY_DOMAIN_CHROME);
+  }
+}
+
+void PolicyServiceWatcher::StopWatchingInternal() {
+  policy_service_->RemoveObserver(POLICY_DOMAIN_CHROME, this);
+}
+
+#if !defined(OS_CHROMEOS)
+
+scoped_ptr<PolicyServiceWatcher> CreateFromPolicyLoader(
+    const scoped_refptr<base::SingleThreadTaskRunner>&
+        policy_service_task_runner,

[Mattias Nissler (ping if slow), 2015/01/08 09:58:37]

Can you put a comment saying that policy_service_task_runner must be allowed to
perform I/O for this function?

[Łukasz Anforowicz, 2015/01/08 23:09:27]

I think this is more of a restriction for PolicyWatcher::Create (which creates
the OS-specific PolicyLoaders below) and I've already added a comment explaining
this to policy_watcher.h.

From the perspective of CreateFromPolicyLoader, |policy_service_task_runner| is
just passed through to the constructor of PolicyServiceWatcher (which doesn't
have the I/O restriction).

I did make small changes here though:
1) added a comment for the function
2) moved schema wrapping and added a TODO comment to make it chromoting specific
in the future

+    scoped_ptr<AsyncPolicyLoader> async_policy_loader) {
+  scoped_ptr<SchemaRegistry> schema_registry(new SchemaRegistry());
+  schema_registry->RegisterComponent(PolicyServiceWatcher::GetPolicyNamespace(),
+                                     Schema::Wrap(GetChromeSchemaData()));
+
+  scoped_ptr<AsyncPolicyProvider> policy_provider(new AsyncPolicyProvider(
+      schema_registry.get(), async_policy_loader.Pass()));
+  policy_provider->Init(schema_registry.get());
+
+  PolicyServiceImpl::Providers providers;
+  providers.push_back(policy_provider.get());
+  scoped_ptr<PolicyService> policy_service(new PolicyServiceImpl(providers));
+
+  return make_scoped_ptr(new PolicyServiceWatcher(
+      policy_service_task_runner, policy_service.Pass(), policy_provider.Pass(),
+      schema_registry.Pass()));
+}
+
+#endif
+
+}  // anonymous namespace
+
+scoped_ptr<PolicyWatcher> PolicyWatcher::Create(
+    policy::PolicyService* policy_service,
+    const scoped_refptr<base::SingleThreadTaskRunner>&
+        policy_service_task_runner) {

[Mattias Nissler (ping if slow), 2015/01/08 09:58:37]

In this case, the task runner should probably be named network_task_runner so
it's clear what it is?

[Łukasz Anforowicz, 2015/01/08 23:09:27]

Yes - makes sense.  Thanks.

+#if defined(OS_CHROMEOS)
+  DCHECK(policy_service != nullptr);
+  return make_scoped_ptr(new PolicyServiceWatcher(
+      content::BrowserThread::GetMessageLoopProxyForThread(
+          content::BrowserThread::UI),
+      policy_service));
+#elif defined(OS_WIN)
+  DCHECK(policy_service == nullptr);
+  static const wchar_t kRegistryKey[] = L"SOFTWARE\\Policies\\Google\\Chrome";
+  return CreateFromPolicyLoader(
+      policy_service_task_runner,
+      scoped_ptr<AsyncPolicyLoader>(
+          PolicyLoaderWin::Create(policy_service_task_runner, kRegistryKey)));
+#elif defined(OS_MACOSX)
+  CFStringRef bundle_id = CFSTR("com.google.Chrome");
+  DCHECK(policy_service == nullptr);
+  return CreateFromPolicyLoader(
+      policy_service_task_runner,
+      make_scoped_ptr(new PolicyLoaderMac(
+          policy_service_task_runner,
+          policy::PolicyLoaderMac::GetManagedPolicyPath(bundle_id),
+          new MacPreferences(), bundle_id)));
+#elif defined(OS_POSIX) && !defined(OS_ANDROID)
+  DCHECK(policy_service == nullptr);
+  // Always read the Chrome policies (even on Chromium) so that policy
+  // enforcement can't be bypassed by running Chromium.
+  static const base::FilePath::CharType kPolicyDir[] =
+      FILE_PATH_LITERAL("/etc/opt/chrome/policies");
+  return CreateFromPolicyLoader(
+      policy_service_task_runner,
+      make_scoped_ptr(new ConfigDirPolicyLoader(policy_service_task_runner,
+                                                base::FilePath(kPolicyDir),
+                                                POLICY_SCOPE_MACHINE)));
+#else
+#error OS that is not yet supported by PolicyWatcher code.
+#endif
+}
+
+}  // namespace policy_hack
+}  // namespace remoting