[fsp] Add support for observing entries and notifying about changes.

chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc

Index: chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc
diff --git a/chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc b/chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc
index e8fafd7a408e200fda0571cb05feca3f1e2da6da..384e38778aee7694766e3153b864ba7d7022bf38 100644
--- a/chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc
+++ b/chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_api.cc
@@ -24,6 +24,12 @@ using chromeos::file_system_provider::RequestValue;
 using chromeos::file_system_provider::Service;
 
 namespace extensions {
+namespace {
+
+const char kNotifyFailedErrorMessage[] =
+    "Sending a response for the request failed.";
+
+}  // namespace
 
 bool FileSystemProviderMountFunction::RunSync() {
   using api::file_system_provider::Mount::Params;
@@ -116,6 +122,41 @@ bool FileSystemProviderGetAllFunction::RunSync() {
   return true;
 }
 
+bool FileSystemProviderNotifyFunction::RunSync() {
+  using api::file_system_provider::Notify::Params;
+  scoped_ptr<Params> params(Params::Create(*args_));
+  EXTENSION_FUNCTION_VALIDATE(params);
+
+  Service* const service = Service::Get(GetProfile());
+  DCHECK(service);
+  if (!service)
+    return false;
+
+  ProvidedFileSystemInterface* const file_system =
+      service->GetProvidedFileSystem(extension_id(),
+                                     params->options.file_system_id);
+  if (!file_system) {
+    base::ListValue* const result = new base::ListValue();
+    result->Append(CreateError(kNotFoundErrorName, kNotifyFailedErrorMessage));
+    SetResult(result);
+    return true;
+  }
+
+  FOR_EACH_OBSERVER(
+      chromeos::file_system_provider::ProvidedFileSystemInterface::Observer,
+      *file_system->GetObservers(),
+      OnEntryChanged(
+          base::FilePath::FromUTF8Unsafe(params->options.observed_path),
+          chromeos::file_system_provider::ProvidedFileSystemInterface::
+              CHANGED /* TODO(mtomasz) */,
+          chromeos::file_system_provider::ProvidedFileSystemInterface::
+              ChildChanges()));
+
+  base::ListValue* const result = new base::ListValue();
+  SetResult(result);
+  return true;
+}
+
 bool FileSystemProviderInternalUnmountRequestedSuccessFunction::RunWhenValid() {
   using api::file_system_provider_internal::UnmountRequestedSuccess::Params;
   scoped_ptr<Params> params(Params::Create(*args_));