Reland "Observe file modifications in FileChangeService"

This is a reland of c52857a9

The original cl missed calls to run_loop.Run() in test methods
that wrote to a file, and waited for the write to finish.

TBR=dats@chromium.org

Original change's description:
> Observe file modifications in FileChangeService
>
> Adds OnFileModified observer interface to FileChangeServiceObserver
> called when the file is written, truncated, or copied to.
>
> Fixes file change service unit tests to verify that mocked observer
> methods actually get called. The observers were previously not
> getting invoked because the test suite did not set up fake chrome
> user manager, so user account IDs were not correctly mapped to the
> associated test profile, which is something
> ObservableFileSystemOperationImpl depends on to get the
> FileChangeService to notify of file changes.
>
> BUG=1139115
>
> Change-Id: I9829db0a496eec301a7f7547ac74f61bc1a18bdf
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2603467
> Reviewed-by: Sergei Datsenko <dats@chromium.org>
> Reviewed-by: David Black <dmblack@google.com>
> Commit-Queue: Toni Baržić <tbarzic@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#839697}

Bug: 1139115
Change-Id: I70e23cd1b11c9168ee99d8ed314942d25bd4a004
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2607415
Commit-Queue: Toni Baržić <tbarzic@chromium.org>
Reviewed-by: David Black <dmblack@google.com>
Cr-Commit-Position: refs/heads/master@{#839780}

chrome/browser/chromeos/fileapi/file_change_service.cc

@@ -18,6 +18,11 @@ void FileChangeService::RemoveObserver(FileChangeServiceObserver* observer) {
   observer_list_.RemoveObserver(observer);
 }
 
+void FileChangeService::NotifyFileModified(const storage::FileSystemURL& url) {
+  for (FileChangeServiceObserver& observer : observer_list_)
+    observer.OnFileModified(url);
+}
+
 void FileChangeService::NotifyFileCopied(const storage::FileSystemURL& src,
                                          const storage::FileSystemURL& dst) {
   for (FileChangeServiceObserver& observer : observer_list_)

chrome/browser/chromeos/fileapi/file_change_service.h

@@ -25,6 +25,9 @@ class FileChangeService : public KeyedService {
   void AddObserver(FileChangeServiceObserver* observer);
   void RemoveObserver(FileChangeServiceObserver* observer);
 
+  // Notifies the service that a file identified by `url` has been modified.
+  void NotifyFileModified(const storage::FileSystemURL& url);
+
   // Notifies the service that a file has been copied from `src` to `dst`.
   void NotifyFileCopied(const storage::FileSystemURL& src,
                         const storage::FileSystemURL& dst);

chrome/browser/chromeos/fileapi/file_change_service_observer.h

@@ -16,6 +16,10 @@ namespace chromeos {
 // An interface for an observer which receives `FileChangeService` events.
 class FileChangeServiceObserver : public base::CheckedObserver {
  public:
+  // Invoked when a file identified by `url` has been modified. Note that this
+  // will not get called on file creation or deletion.
+  virtual void OnFileModified(const storage::FileSystemURL& url) {}
+
   // Invoked when a file has been copied from `src` to `dst`.
   virtual void OnFileCopied(const storage::FileSystemURL& src,
                             const storage::FileSystemURL& dst) {}

chrome/browser/chromeos/fileapi/observable_file_system_operation_impl.cc

@@ -16,6 +16,7 @@ namespace chromeos {
 namespace {
 
 using StatusCallback = storage::FileSystemOperation::StatusCallback;
+using WriteCallback = storage::FileSystemOperation::WriteCallback;
 
 // Helpers ---------------------------------------------------------------------
 
@@ -34,8 +35,10 @@ void NotifyFileCopiedOnUiThread(const AccountId& account_id,
                                 const storage::FileSystemURL& dst) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   FileChangeService* service = GetFileChangeService(account_id);
-  if (service)
+  if (service) {
+    service->NotifyFileModified(dst);
     service->NotifyFileCopied(src, dst);
+  }
 }
 
 // Notifies the `FileChangeService` associated with the given `account_id` of a
@@ -50,6 +53,28 @@ void NotifyFileMovedOnUiThread(const AccountId& account_id,
     service->NotifyFileMoved(src, dst);
 }
 
+// Notifies the `FileChangeService` associated with the given `account_id` of a
+// file under `url` getting modified. This method may only be called from the
+// browser UI thread.
+void NotifyFileModifiedOnUiThread(const AccountId& account_id,
+                                  const storage::FileSystemURL& url) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  FileChangeService* service = GetFileChangeService(account_id);
+  if (service)
+    service->NotifyFileModified(url);
+}
+
+// Returns a `WriteCallback` which runs the specified callbacks in order.
+WriteCallback RunInOrderCallback(WriteCallback a, WriteCallback b) {
+  return base::BindRepeating(
+      [](WriteCallback a, WriteCallback b, base::File::Error result,
+         int64_t bytes, bool complete) {
+        std::move(a).Run(result, bytes, complete);
+        std::move(b).Run(result, bytes, complete);
+      },
+      std::move(a), std::move(b));
+}
+
 // Returns a `StatusCallback` which runs the specified callbacks in order.
 StatusCallback RunInOrderCallback(StatusCallback a, StatusCallback b) {
   return base::BindOnce(
@@ -73,6 +98,21 @@ StatusCallback RunOnUiThreadOnSuccessCallback(base::OnceClosure closure) {
       std::move(closure));
 }
 
+// Returns a `WriteCallback` which runs the specified `closure` on the browser
+// UI thread if `complete` is set.
+WriteCallback RunOnUiThreadOnCompleteCallback(
+    const base::RepeatingClosure& closure) {
+  return base::BindRepeating(
+      [](const base::RepeatingClosure& closure, base::File::Error result,
+         int64_t bytes, bool complete) {
+        if (complete && result == base::File::FILE_OK) {
+          auto task_runner = content::GetUIThreadTaskRunner({});
+          task_runner->PostTask(FROM_HERE, std::move(closure));
+        }
+      },
+      std::move(closure));
+}
+
 }  // namespace
 
 // ObservableFileSystemOperationImpl -------------------------------------------
@@ -144,4 +184,39 @@ void ObservableFileSystemOperationImpl::MoveFileLocal(
           std::move(callback)));
 }
 
+void ObservableFileSystemOperationImpl::WriteBlob(
+    const storage::FileSystemURL& url,
+    std::unique_ptr<storage::FileWriterDelegate> writer_delegate,
+    std::unique_ptr<storage::BlobReader> blob_reader,
+    const WriteCallback& callback) {
+  storage::FileSystemOperationImpl::WriteBlob(
+      url, std::move(writer_delegate), std::move(blob_reader),
+      RunInOrderCallback(RunOnUiThreadOnCompleteCallback(base::BindRepeating(
+                             &NotifyFileModifiedOnUiThread, account_id_, url)),
+                         std::move(callback)));
+}
+
+void ObservableFileSystemOperationImpl::Write(
+    const storage::FileSystemURL& url,
+    std::unique_ptr<storage::FileWriterDelegate> writer_delegate,
+    mojo::ScopedDataPipeConsumerHandle data_pipe,
+    const WriteCallback& callback) {
+  storage::FileSystemOperationImpl::Write(
+      url, std::move(writer_delegate), std::move(data_pipe),
+      RunInOrderCallback(RunOnUiThreadOnCompleteCallback(base::BindRepeating(
+                             &NotifyFileModifiedOnUiThread, account_id_, url)),
+                         std::move(callback)));
+}
+
+void ObservableFileSystemOperationImpl::Truncate(
+    const storage::FileSystemURL& url,
+    int64_t length,
+    StatusCallback callback) {
+  storage::FileSystemOperationImpl::Truncate(
+      url, length,
+      RunInOrderCallback(RunOnUiThreadOnSuccessCallback(base::BindOnce(
+                             &NotifyFileModifiedOnUiThread, account_id_, url)),
+                         std::move(callback)));
+}
+
 }  // namespace chromeos

chrome/browser/chromeos/fileapi/observable_file_system_operation_impl.h

@@ -49,6 +49,17 @@ class ObservableFileSystemOperationImpl
                      const storage::FileSystemURL& dst,
                      CopyOrMoveOption option,
                      StatusCallback callback) override;
+  void WriteBlob(const storage::FileSystemURL& url,
+                 std::unique_ptr<storage::FileWriterDelegate> writer_delegate,
+                 std::unique_ptr<storage::BlobReader> blob_reader,
+                 const WriteCallback& callback) override;
+  void Write(const storage::FileSystemURL& url,
+             std::unique_ptr<storage::FileWriterDelegate> writer_delegate,
+             mojo::ScopedDataPipeConsumerHandle data_pipe,
+             const WriteCallback& callback) override;
+  void Truncate(const storage::FileSystemURL& url,
+                int64_t length,
+                StatusCallback callback) override;
 
   const AccountId account_id_;
   base::WeakPtrFactory<ObservableFileSystemOperationImpl> weak_factory_{this};