Bug 1857288 - Make ownership transfer after creation of AsyncPanZoomController more explicit. r=dholbert

Differential Revision: https://phabricator.services.mozilla.com/D190378

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -356,11 +356,12 @@ void APZCTreeManager::NotifyLayerTreeRemoved(LayersId aLayersId) {
   }
 }
 
-AsyncPanZoomController* APZCTreeManager::NewAPZCInstance(
+already_AddRefed<AsyncPanZoomController> APZCTreeManager::NewAPZCInstance(
     LayersId aLayersId, GeckoContentController* aController) {
-  return new AsyncPanZoomController(
-      aLayersId, this, mInputQueue, aController,
-      AsyncPanZoomController::USE_GESTURE_DETECTOR);
+  return MakeRefPtr<AsyncPanZoomController>(
+             aLayersId, this, mInputQueue, aController,
+             AsyncPanZoomController::USE_GESTURE_DETECTOR)
+      .forget();
 }
 
 void APZCTreeManager::SetTestSampleTime(const Maybe<TimeStamp>& aTime) {
@@ -1155,7 +1156,7 @@ HitTestingTreeNode* APZCTreeManager::PrepareNodeForLayer(
     return node;
   }
 
-  AsyncPanZoomController* apzc = nullptr;
+  RefPtr<AsyncPanZoomController> apzc;
   // If we get here, aLayer is a scrollable layer and somebody
   // has registered a GeckoContentController for it, so we need to ensure
   // it has an APZC instance to manage its scrolling.
@@ -1173,9 +1174,9 @@ HitTestingTreeNode* APZCTreeManager::PrepareNodeForLayer(
     apzc = insertResult.first->second.apzc;
     PrintLayerInfo(aLayer);
   }
-  APZCTM_LOG("Found APZC %p for layer %p with identifiers %" PRIx64 " %" PRId64
-             "\n",
-             apzc, aLayer.GetLayer(), uint64_t(guid.mLayersId), guid.mScrollId);
+  APZCTM_LOG(
+      "Found APZC %p for layer %p with identifiers %" PRIx64 " %" PRId64 "\n",
+      apzc.get(), aLayer.GetLayer(), uint64_t(guid.mLayersId), guid.mScrollId);
 
   // If we haven't encountered a layer already with the same metrics, then we
   // need to do the full reuse-or-make-an-APZC algorithm, which is contained
@@ -1246,9 +1247,10 @@ HitTestingTreeNode* APZCTreeManager::PrepareNodeForLayer(
       aState.mZoomAnimationId = Nothing();
     }
 
-    APZCTM_LOG(
-        "Using APZC %p for layer %p with identifiers %" PRIx64 " %" PRId64 "\n",
-        apzc, aLayer.GetLayer(), uint64_t(aLayersId), aMetrics.GetScrollId());
+    APZCTM_LOG("Using APZC %p for layer %p with identifiers %" PRIx64
+               " %" PRId64 "\n",
+               apzc.get(), aLayer.GetLayer(), uint64_t(aLayersId),
+               aMetrics.GetScrollId());
 
     apzc->NotifyLayersUpdated(aLayer.Metadata(), aState.mIsFirstPaint,
                               aLayersId == aState.mOriginatingLayersId);

gfx/layers/apz/src/APZCTreeManager.h

@@ -529,7 +529,7 @@ class APZCTreeManager : public IAPZCTreeManager, public APZInputBridge {
   void UnlockTree() MOZ_CAPABILITY_RELEASE(mTreeLock);
 
   // Protected hooks for gtests subclass
-  virtual AsyncPanZoomController* NewAPZCInstance(
+  virtual already_AddRefed<AsyncPanZoomController> NewAPZCInstance(
       LayersId aLayersId, GeckoContentController* aController);
 
  public:

gfx/layers/apz/test/gtest/APZTestCommon.cpp

@@ -6,10 +6,11 @@
 
 #include "APZTestCommon.h"
 
-AsyncPanZoomController* TestAPZCTreeManager::NewAPZCInstance(
+already_AddRefed<AsyncPanZoomController> TestAPZCTreeManager::NewAPZCInstance(
     LayersId aLayersId, GeckoContentController* aController) {
   MockContentControllerDelayed* mcc =
       static_cast<MockContentControllerDelayed*>(aController);
-  return new TestAsyncPanZoomController(
-      aLayersId, mcc, this, AsyncPanZoomController::USE_GESTURE_DETECTOR);
+  return MakeRefPtr<TestAsyncPanZoomController>(
+             aLayersId, mcc, this, AsyncPanZoomController::USE_GESTURE_DETECTOR)
+      .forget();
 }

gfx/layers/apz/test/gtest/APZTestCommon.h

@@ -268,7 +268,7 @@ class TestAPZCTreeManager : public APZCTreeManager {
   }
 
  protected:
-  AsyncPanZoomController* NewAPZCInstance(
+  already_AddRefed<AsyncPanZoomController> NewAPZCInstance(
       LayersId aLayersId, GeckoContentController* aController) override;
 
   SampleTime GetFrameTime() override { return mcc->GetSampleTime(); }