Refactor the various ways to control what users can do to extensions.

chrome/browser/extensions/management_policy.cc

+// Copyright (c) 2012 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 "chrome/browser/extensions/management_policy.h"
+
+namespace extensions {
+ManagementPolicy::ManagementPolicy() {
+}
+
+ManagementPolicy::~ManagementPolicy() {
+}
+
+bool ManagementPolicy::Provider::UserMayLoad(const Extension* extension,
+                                             string16* error) const {
+  return true;
+}
+
+bool ManagementPolicy::Provider::UserMayModifySettings(
+    const Extension* extension, string16* error) const {
+  return true;
+}
+
+bool ManagementPolicy::Provider::MustRemainEnabled(const Extension* extension,
+                                                   string16* error) const {
+  return false;
+}
+
+void ManagementPolicy::RegisterProvider(Provider* provider) {
+  providers_.insert(provider);
+}
+
+void ManagementPolicy::UnregisterProvider(Provider* provider) {
+  providers_.erase(provider);
+}
+
+bool ManagementPolicy::UserMayLoad(const Extension* extension,
+                                   string16* error) const {
+  for (ProviderList::const_iterator it = providers_.begin();
+      it != providers_.end(); ++it) {
+    if (!(*it)->UserMayLoad(extension, error)) {
+      // The extension may be NULL in testing.
+      std::string id = extension ? extension->id() : "[test]";
+      DLOG(WARNING) << "Installation of extension " << id
+                    << " prohibited by " << (*it)->GetPolicyProviderName();
+      return false;
+    }
+  }
+  return true;
+}
+
+bool ManagementPolicy::UserMayModifySettings(const Extension* extension,
+                                             string16* error) const {
+  for (ProviderList::const_iterator it = providers_.begin();
+      it != providers_.end(); ++it) {
+    if (!(*it)->UserMayModifySettings(extension, error)) {
+      // The extension may be NULL in testing.
+      std::string id = extension ? extension->id() : "[test]";
+      DLOG(WARNING) << "Modification of extension " << id
+                    << " prohibited by " << (*it)->GetPolicyProviderName();
+      return false;
+    }
+  }
+  return true;
+}
+
+bool ManagementPolicy::MustRemainEnabled(const Extension* extension,
+                                         string16* error) const {
+  for (ProviderList::const_iterator it = providers_.begin();
+      it != providers_.end(); ++it) {
+      // The extension may be NULL in testing.
+      std::string id = extension ? extension->id() : "[test]";
+      if ((*it)->MustRemainEnabled(extension, error)) {
+      DLOG(WARNING) << "Extension " << id
+                    << " required to remain enabled by "
+                    << (*it)->GetPolicyProviderName();
+      return true;
+    }
+  }
+  return false;
+}
+
+void ManagementPolicy::UnregisterAllProviders() {
+  providers_.clear();
+}
+
+int ManagementPolicy::GetNumProviders() const {
+  return providers_.size();
+}
+}  // namespace