Migrate FileSystemDispatcher to use GC mojo wrappers.

No behavior change. This CL reduces potential risks of use-after-free
bugs. This CL is followup CL. FileSystemDispatcher was already
migrated before, but there were remaining mojo objects.

Bug: 1049056
Change-Id: Ib9933ee186ecca6d5cc73bf70a6d9a5ee429c010
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2211564Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Minoru Chikamune <chikamune@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771232}

third_party/blink/renderer/modules/filesystem/file_system_dispatcher.cc

@@ -331,7 +331,8 @@ void FileSystemDispatcher::Truncate(const KURL& path,
                                     int64_t offset,
                                     int* request_id_out,
                                     StatusCallback callback) {
-  mojo::Remote<mojom::blink::FileSystemCancellableOperation> op_remote;
+  HeapMojoRemote<mojom::blink::FileSystemCancellableOperation> op_remote(
+      GetSupplementable());
   // See https://bit.ly/2S0zRAS for task types
   mojo::PendingReceiver<mojom::blink::FileSystemCancellableOperation>
       op_receiver = op_remote.BindNewPipeAndPassReceiver(
@@ -341,7 +342,8 @@ void FileSystemDispatcher::Truncate(const KURL& path,
   op_remote.set_disconnect_handler(
       WTF::Bind(&FileSystemDispatcher::RemoveOperationRemote,
                 WrapWeakPersistent(this), operation_id));
-  cancellable_operations_.insert(operation_id, std::move(op_remote));
+  cancellable_operations_.insert(operation_id,
+                                 WrapDisallowNew(std::move(op_remote)));
   GetFileSystemManager().Truncate(
       path, offset, std::move(op_receiver),
       WTF::Bind(&FileSystemDispatcher::DidTruncate, WrapWeakPersistent(this),
@@ -365,7 +367,8 @@ void FileSystemDispatcher::Write(const KURL& path,
                                  int* request_id_out,
                                  const WriteCallback& success_callback,
                                  StatusCallback error_callback) {
-  mojo::Remote<mojom::blink::FileSystemCancellableOperation> op_remote;
+  HeapMojoRemote<mojom::blink::FileSystemCancellableOperation> op_remote(
+      GetSupplementable());
   // See https://bit.ly/2S0zRAS for task types
   scoped_refptr<base::SequencedTaskRunner> task_runner =
       GetSupplementable()->GetTaskRunner(blink::TaskType::kMiscPlatformAPI);
@@ -375,7 +378,8 @@ void FileSystemDispatcher::Write(const KURL& path,
   op_remote.set_disconnect_handler(
       WTF::Bind(&FileSystemDispatcher::RemoveOperationRemote,
                 WrapWeakPersistent(this), operation_id));
-  cancellable_operations_.insert(operation_id, std::move(op_remote));
+  cancellable_operations_.insert(operation_id,
+                                 WrapDisallowNew(std::move(op_remote)));
 
   mojo::PendingRemote<mojom::blink::FileSystemOperationListener> listener;
   mojo::PendingReceiver<mojom::blink::FileSystemOperationListener> receiver =
@@ -419,9 +423,10 @@ void FileSystemDispatcher::Cancel(int request_id_to_cancel,
     return;
   }
   cancellable_operations_.find(request_id_to_cancel)
-      ->value->Cancel(WTF::Bind(&FileSystemDispatcher::DidCancel,
-                                WrapWeakPersistent(this), std::move(callback),
-                                request_id_to_cancel));
+      ->value->Value()
+      ->Cancel(WTF::Bind(&FileSystemDispatcher::DidCancel,
+                         WrapWeakPersistent(this), std::move(callback),
+                         request_id_to_cancel));
 }
 
 void FileSystemDispatcher::CreateSnapshotFile(
@@ -448,6 +453,7 @@ void FileSystemDispatcher::CreateSnapshotFileSync(
 
 void FileSystemDispatcher::Trace(Visitor* visitor) const {
   visitor->Trace(file_system_manager_);
+  visitor->Trace(cancellable_operations_);
   visitor->Trace(op_listeners_);
   Supplement<ExecutionContext>::Trace(visitor);
 }

third_party/blink/renderer/modules/filesystem/file_system_dispatcher.h

@@ -10,7 +10,9 @@
 #include "mojo/public/cpp/bindings/pending_remote.h"
 #include "third_party/blink/public/mojom/filesystem/file_system.mojom-blink.h"
 #include "third_party/blink/renderer/modules/filesystem/file_system_callbacks.h"
+#include "third_party/blink/renderer/platform/heap/disallow_new_wrapper.h"
 #include "third_party/blink/renderer/platform/heap/handle.h"
+#include "third_party/blink/renderer/platform/heap/heap_allocator.h"
 #include "third_party/blink/renderer/platform/mojo/heap_mojo_remote.h"
 #include "third_party/blink/renderer/platform/mojo/heap_mojo_unique_receiver_set.h"
 #include "third_party/blink/renderer/platform/supplementable.h"
@@ -201,7 +203,9 @@ class FileSystemDispatcher : public GarbageCollected<FileSystemDispatcher>,
 
   HeapMojoRemote<mojom::blink::FileSystemManager> file_system_manager_;
   using OperationsMap =
-      HashMap<int, mojo::Remote<mojom::blink::FileSystemCancellableOperation>>;
+      HeapHashMap<int,
+                  Member<DisallowNewWrapper<HeapMojoRemote<
+                      mojom::blink::FileSystemCancellableOperation>>>>;
   OperationsMap cancellable_operations_;
   int next_operation_id_;
   HeapMojoUniqueReceiverSet<mojom::blink::FileSystemOperationListener>