Migrate FileSystemDispatcher to use GC mojo wrappers.

No behavior change. This CL reduces potential risks of use-after-free bugs.

Bug: 1049056
Change-Id: I2a4e8323ce14e7f557ff2de93192a0061e879cab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2136570Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Minoru Chikamune <chikamune@chromium.org>
Cr-Commit-Position: refs/heads/master@{#756594}

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

@@ -73,7 +73,10 @@ class FileSystemDispatcher::ReadDirectoryListener
 };
 
 FileSystemDispatcher::FileSystemDispatcher(ExecutionContext& context)
-    : Supplement<ExecutionContext>(context), next_operation_id_(1) {}
+    : Supplement<ExecutionContext>(context),
+      file_system_manager_(&context),
+      next_operation_id_(1),
+      op_listeners_(&context) {}
 
 // static
 const char FileSystemDispatcher::kSupplementName[] = "FileSystemDispatcher";
@@ -93,7 +96,7 @@ FileSystemDispatcher& FileSystemDispatcher::From(ExecutionContext* context) {
 FileSystemDispatcher::~FileSystemDispatcher() = default;
 
 mojom::blink::FileSystemManager& FileSystemDispatcher::GetFileSystemManager() {
-  if (!file_system_manager_) {
+  if (!file_system_manager_.is_bound()) {
     // See https://bit.ly/2S0zRAS for task types
     mojo::PendingReceiver<mojom::blink::FileSystemManager> receiver =
         file_system_manager_.BindNewPipeAndPassReceiver(
@@ -103,7 +106,7 @@ mojom::blink::FileSystemManager& FileSystemDispatcher::GetFileSystemManager() {
     GetSupplementable()->GetBrowserInterfaceBroker().GetInterface(
         std::move(receiver));
   }
-  DCHECK(file_system_manager_);
+  DCHECK(file_system_manager_.is_bound());
   return *file_system_manager_.get();
 }
 
@@ -443,6 +446,12 @@ void FileSystemDispatcher::CreateSnapshotFileSync(
                         std::move(listener));
 }
 
+void FileSystemDispatcher::Trace(Visitor* visitor) {
+  visitor->Trace(file_system_manager_);
+  visitor->Trace(op_listeners_);
+  Supplement<ExecutionContext>::Trace(visitor);
+}
+
 void FileSystemDispatcher::DidOpenFileSystem(
     std::unique_ptr<FileSystemCallbacks> callbacks,
     const String& name,

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

@@ -8,11 +8,12 @@
 #include <memory>
 
 #include "mojo/public/cpp/bindings/pending_remote.h"
-#include "mojo/public/cpp/bindings/remote.h"
-#include "mojo/public/cpp/bindings/unique_receiver_set.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/handle.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/mojo/heap_mojo_wrapper_mode.h"
 #include "third_party/blink/renderer/platform/supplementable.h"
 
 namespace WTF {
@@ -144,6 +145,8 @@ class FileSystemDispatcher : public GarbageCollected<FileSystemDispatcher>,
       const KURL& file_path,
       std::unique_ptr<SnapshotFileCallbackBase> callbacks);
 
+  void Trace(Visitor*) override;
+
  private:
   class WriteListener;
   class ReadDirectoryListener;
@@ -197,12 +200,17 @@ class FileSystemDispatcher : public GarbageCollected<FileSystemDispatcher>,
 
   void Prefinalize();
 
-  mojo::Remote<mojom::blink::FileSystemManager> file_system_manager_;
+  HeapMojoRemote<mojom::blink::FileSystemManager,
+                 HeapMojoWrapperMode::kWithoutContextObserver>
+      file_system_manager_;
   using OperationsMap =
       HashMap<int, mojo::Remote<mojom::blink::FileSystemCancellableOperation>>;
   OperationsMap cancellable_operations_;
   int next_operation_id_;
-  mojo::UniqueReceiverSet<mojom::blink::FileSystemOperationListener>
+  HeapMojoUniqueReceiverSet<
+      mojom::blink::FileSystemOperationListener,
+      std::default_delete<mojom::blink::FileSystemOperationListener>,
+      HeapMojoWrapperMode::kWithoutContextObserver>
       op_listeners_;
 };