mediaview: Implement ArcDocumentsProviderWatcherManager.

ArcDocumentsProviderWatcherManager simply calls ArcDocumentsProviderRoot.

BUG=chromium:684233
TEST=trybot
TEST=Media view refreshes on media provider changes.

Review-Url: https://codereview.chromium.org/2709013003
Cr-Commit-Position: refs/heads/master@{#454598}
(cherry picked from commit 7b44260)

Review-Url: https://codereview.chromium.org/2736613002 .
Cr-Commit-Position: refs/branch-heads/3029@{#14}
Cr-Branched-From: 939b32e-refs/heads/master@{#454471}

chrome/browser/chromeos/BUILD.gn

@@ -273,6 +273,8 @@ source_set("chromeos") {
     "arc/fileapi/arc_documents_provider_root_map.h",
     "arc/fileapi/arc_documents_provider_util.cc",
     "arc/fileapi/arc_documents_provider_util.h",
+    "arc/fileapi/arc_documents_provider_watcher_manager.cc",
+    "arc/fileapi/arc_documents_provider_watcher_manager.h",
     "arc/fileapi/arc_file_system_mounter.cc",
     "arc/fileapi/arc_file_system_mounter.h",
     "arc/fileapi/arc_file_system_operation_runner.cc",

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_backend_delegate.cc

@@ -19,7 +19,7 @@ using content::BrowserThread;
 namespace arc {
 
 ArcDocumentsProviderBackendDelegate::ArcDocumentsProviderBackendDelegate()
-    : async_file_util_(&roots_) {}
+    : async_file_util_(&roots_), watcher_manager_(&roots_) {}
 
 ArcDocumentsProviderBackendDelegate::~ArcDocumentsProviderBackendDelegate() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
@@ -57,8 +57,7 @@ ArcDocumentsProviderBackendDelegate::CreateFileStreamWriter(
 storage::WatcherManager* ArcDocumentsProviderBackendDelegate::GetWatcherManager(
     storage::FileSystemType type) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  NOTREACHED();  // Non-watchable file system.
-  return nullptr;
+  return &watcher_manager_;
 }
 
 void ArcDocumentsProviderBackendDelegate::GetRedirectURLForContents(

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_backend_delegate.h

@@ -10,6 +10,7 @@
 #include "base/macros.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_async_file_util.h"
 #include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root_map.h"
+#include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_watcher_manager.h"
 #include "chrome/browser/chromeos/fileapi/file_system_backend_delegate.h"
 
 namespace arc {
@@ -42,6 +43,7 @@ class ArcDocumentsProviderBackendDelegate
  private:
   ArcDocumentsProviderRootMap roots_;
   ArcDocumentsProviderAsyncFileUtil async_file_util_;
+  ArcDocumentsProviderWatcherManager watcher_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcDocumentsProviderBackendDelegate);
 };

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_watcher_manager.cc

@@ -0,0 +1,72 @@
+// Copyright 2017 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/arc/fileapi/arc_documents_provider_watcher_manager.h"
+
+#include "base/files/file.h"
+#include "base/files/file_path.h"
+#include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h"
+#include "chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root_map.h"
+#include "content/public/browser/browser_thread.h"
+#include "storage/browser/fileapi/file_system_url.h"
+
+using content::BrowserThread;
+using storage::FileSystemURL;
+
+namespace arc {
+
+ArcDocumentsProviderWatcherManager::ArcDocumentsProviderWatcherManager(
+    ArcDocumentsProviderRootMap* roots)
+    : roots_(roots), weak_ptr_factory_(this) {}
+
+ArcDocumentsProviderWatcherManager::~ArcDocumentsProviderWatcherManager() {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+}
+
+void ArcDocumentsProviderWatcherManager::AddWatcher(
+    const FileSystemURL& url,
+    bool recursive,
+    const StatusCallback& callback,
+    const NotificationCallback& notification_callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  if (recursive) {
+    // Recursive watching is not supported.
+    callback.Run(base::File::FILE_ERROR_INVALID_OPERATION);
+    return;
+  }
+
+  base::FilePath path;
+  ArcDocumentsProviderRoot* root = roots_->ParseAndLookup(url, &path);
+  if (!root) {
+    callback.Run(base::File::FILE_ERROR_NOT_FOUND);
+    return;
+  }
+
+  root->AddWatcher(path, notification_callback, callback);
+}
+
+void ArcDocumentsProviderWatcherManager::RemoveWatcher(
+    const FileSystemURL& url,
+    bool recursive,
+    const StatusCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  if (recursive) {
+    // Recursive watching is not supported.
+    callback.Run(base::File::FILE_ERROR_INVALID_OPERATION);
+    return;
+  }
+
+  base::FilePath path;
+  ArcDocumentsProviderRoot* root = roots_->ParseAndLookup(url, &path);
+  if (!root) {
+    callback.Run(base::File::FILE_ERROR_NOT_FOUND);
+    return;
+  }
+
+  root->RemoveWatcher(path, callback);
+}
+
+}  // namespace arc

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_watcher_manager.h

@@ -0,0 +1,47 @@
+// Copyright 2017 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.
+
+#ifndef CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_DOCUMENTS_PROVIDER_WATCHER_MANAGER_H_
+#define CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_DOCUMENTS_PROVIDER_WATCHER_MANAGER_H_
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "storage/browser/fileapi/watcher_manager.h"
+
+namespace arc {
+
+class ArcDocumentsProviderRootMap;
+
+// The implementation of storage::WatcherManager for ARC documents provider
+// filesystem.
+//
+// Note that this WatcherManager is not always correct. See comments at
+// ArcDocumentsProviderRoot::AddWatcher().
+class ArcDocumentsProviderWatcherManager : public storage::WatcherManager {
+ public:
+  explicit ArcDocumentsProviderWatcherManager(
+      ArcDocumentsProviderRootMap* roots);
+  ~ArcDocumentsProviderWatcherManager() override;
+
+  // storage::WatcherManager overrides.
+  void AddWatcher(const storage::FileSystemURL& url,
+                  bool recursive,
+                  const StatusCallback& callback,
+                  const NotificationCallback& notification_callback) override;
+  void RemoveWatcher(const storage::FileSystemURL& url,
+                     bool recursive,
+                     const StatusCallback& callback) override;
+
+ private:
+  // Owned by ArcDocumentsProviderBackendDelegate.
+  ArcDocumentsProviderRootMap* const roots_;
+
+  base::WeakPtrFactory<ArcDocumentsProviderWatcherManager> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(ArcDocumentsProviderWatcherManager);
+};
+
+}  // namespace arc
+
+#endif  // CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_DOCUMENTS_PROVIDER_WATCHER_MANAGER_H_

chrome/browser/chromeos/fileapi/file_system_backend.cc

@@ -7,6 +7,7 @@
 #include <stddef.h>
 
 #include <memory>
+#include <utility>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ -301,6 +302,9 @@ storage::WatcherManager* FileSystemBackend::GetWatcherManager(
     return mtp_delegate_->GetWatcherManager(type);
   }
 
+  if (type == storage::kFileSystemTypeArcDocumentsProvider)
+    return arc_documents_provider_delegate_->GetWatcherManager(type);
+
   // TODO(mtomasz): Add support for other backends.
   return NULL;
 }