Make some file_system_provider_capabilities fields optional.

chrome/browser/chromeos/file_system_provider/service.cc

 // 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 "chrome/browser/chromeos/file_system_provider/service.h"
 
 #include "base/files/file_path.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/scoped_user_pref_update.h"
 #include "base/stl_util.h"
@@ skipping 300 matching lines @@
   std::vector<ProvidingExtensionInfo> result;
   for (const auto& extension : registry->enabled_extensions()) {
     if (!extension->permissions_data()->HasAPIPermission(
             extensions::APIPermission::kFileSystemProvider)) {
       continue;
     }
 
     ProvidingExtensionInfo info;
     info.extension_id = extension->id();
     info.name = extension->name();
-    const extensions::FileSystemProviderCapabilities* capabilities =
+    const extensions::FileSystemProviderCapabilities* const capabilities =
         extensions::FileSystemProviderCapabilities::Get(extension.get());
-    info.capabilities = capabilities
-                            ? *capabilities
-                            : extensions::FileSystemProviderCapabilities();
+    DCHECK(capabilities);
+    info.capabilities = *capabilities;
     result.push_back(info);
   }
 
   return result;
 }
 
 void Service::OnExtensionUnloaded(
     content::BrowserContext* browser_context,
     const extensions::Extension* extension,
     extensions::UnloadedExtensionInfo::Reason reason) {
@@ skipping 94 matching lines @@
 }
 
 void Service::OnWatcherListChanged(
     const ProvidedFileSystemInfo& file_system_info,
     const Watchers& watchers) {
   registry_->RememberFileSystem(file_system_info, watchers);
 }
 
 }  // namespace file_system_provider
 }  // namespace chromeos