Migrate IdleDetector to use GC mojo wrappers.

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

Bug: 1049056
Change-Id: I6d13ced16e45f608f044d783529003c700ab3ef1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2131807
Commit-Queue: Minoru Chikamune <chikamune@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757016}

third_party/blink/renderer/modules/idle/idle_detector.cc

@@ -57,14 +57,13 @@ IdleDetector* IdleDetector::Create(ScriptState* script_state,
 }
 
 IdleDetector::IdleDetector(ExecutionContext* context, base::TimeDelta threshold)
-    : ExecutionContextClient(context), threshold_(threshold), receiver_(this) {}
+    : ExecutionContextClient(context),
+      threshold_(threshold),
+      receiver_(this, context),
+      service_(context) {}
 
 IdleDetector::~IdleDetector() = default;
 
-void IdleDetector::Dispose() {
-  StopMonitoring();
-}
-
 const AtomicString& IdleDetector::InterfaceName() const {
   return event_target_names::kIdleDetector;
 }
@@ -98,7 +97,7 @@ ScriptPromise IdleDetector::start(ScriptState* script_state,
 }
 
 void IdleDetector::stop() {
-  StopMonitoring();
+  receiver_.reset();
 }
 
 void IdleDetector::StartMonitoring() {
@@ -110,7 +109,7 @@ void IdleDetector::StartMonitoring() {
   scoped_refptr<base::SingleThreadTaskRunner> task_runner =
       GetExecutionContext()->GetTaskRunner(TaskType::kMiscPlatformAPI);
 
-  if (!service_) {
+  if (!service_.is_bound()) {
     GetExecutionContext()->GetBrowserInterfaceBroker().GetInterface(
         service_.BindNewPipeAndPassReceiver(task_runner));
   }
@@ -124,10 +123,6 @@ void IdleDetector::StartMonitoring() {
       WTF::Bind(&IdleDetector::OnAddMonitor, WrapWeakPersistent(this)));
 }
 
-void IdleDetector::StopMonitoring() {
-  receiver_.reset();
-}
-
 void IdleDetector::OnAddMonitor(mojom::blink::IdleStatePtr state) {
   Update(std::move(state));
 }
@@ -151,6 +146,8 @@ void IdleDetector::Update(mojom::blink::IdleStatePtr state) {
 
 void IdleDetector::Trace(Visitor* visitor) {
   visitor->Trace(state_);
+  visitor->Trace(receiver_);
+  visitor->Trace(service_);
   EventTargetWithInlineData::Trace(visitor);
   ExecutionContextClient::Trace(visitor);
   ActiveScriptWrappable::Trace(visitor);

third_party/blink/renderer/modules/idle/idle_detector.h

@@ -6,8 +6,6 @@
 #define THIRD_PARTY_BLINK_RENDERER_MODULES_IDLE_IDLE_DETECTOR_H_
 
 #include "base/macros.h"
-#include "mojo/public/cpp/bindings/receiver.h"
-#include "mojo/public/cpp/bindings/remote.h"
 #include "third_party/blink/public/mojom/idle/idle_manager.mojom-blink-forward.h"
 #include "third_party/blink/renderer/bindings/core/v8/active_script_wrappable.h"
 #include "third_party/blink/renderer/bindings/core/v8/script_promise.h"
@@ -18,6 +16,8 @@
 #include "third_party/blink/renderer/modules/event_target_modules.h"
 #include "third_party/blink/renderer/modules/idle/idle_state.h"
 #include "third_party/blink/renderer/platform/heap/heap_allocator.h"
+#include "third_party/blink/renderer/platform/mojo/heap_mojo_receiver.h"
+#include "third_party/blink/renderer/platform/mojo/heap_mojo_remote.h"
 #include "third_party/blink/renderer/platform/wtf/functional.h"
 
 namespace blink {
@@ -30,7 +30,6 @@ class IdleDetector final : public EventTargetWithInlineData,
                            public mojom::blink::IdleMonitor {
   USING_GARBAGE_COLLECTED_MIXIN(IdleDetector);
   DEFINE_WRAPPERTYPEINFO();
-  USING_PRE_FINALIZER(IdleDetector, Dispose);
 
  public:
   static IdleDetector* Create(ScriptState*,
@@ -42,8 +41,6 @@ class IdleDetector final : public EventTargetWithInlineData,
 
   ~IdleDetector() override;
 
-  void Dispose();
-
   // EventTarget implementation.
   const AtomicString& InterfaceName() const override;
   ExecutionContext* GetExecutionContext() const override;
@@ -72,12 +69,16 @@ class IdleDetector final : public EventTargetWithInlineData,
 
   // Holds a pipe which the service uses to notify this object
   // when the idle state has changed.
-  mojo::Receiver<mojom::blink::IdleMonitor> receiver_;
+  HeapMojoReceiver<mojom::blink::IdleMonitor,
+                   IdleDetector,
+                   HeapMojoWrapperMode::kWithoutContextObserver>
+      receiver_;
 
   void StartMonitoring();
-  void StopMonitoring();
 
-  mojo::Remote<mojom::blink::IdleManager> service_;
+  HeapMojoRemote<mojom::blink::IdleManager,
+                 HeapMojoWrapperMode::kWithoutContextObserver>
+      service_;
 
   DISALLOW_COPY_AND_ASSIGN(IdleDetector);
 };