diff --git a/gfx/layers/apz/public/APZBridge.h b/gfx/layers/apz/public/APZBridge.h
index 0d668d34c26..5c27db587cc 100644
--- a/gfx/layers/apz/public/APZBridge.h
+++ b/gfx/layers/apz/public/APZBridge.h
@@ -10,6 +10,7 @@
 #include "mozilla/layers/APZPublicUtils.h"  // for APZWheelAction, DispatchToContent
 #include "mozilla/layers/LayersTypes.h"          // for ScrollDirections
 #include "mozilla/layers/ScrollableLayerGuid.h"  // for ScrollableLayerGuid
+#include "nsISupportsImpl.h"
 
 namespace mozilla {
 
@@ -231,6 +232,8 @@ struct APZEventResult {
  * APZCTreeManager overrides and implements these methods directly.
  */
 class APZBridge {
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+
  public:
   using InputBlockCallback = std::function<void(
       uint64_t aInputBlockId, const APZHandledResult& aHandledResult)>;
diff --git a/gfx/layers/apz/public/IAPZCTreeManager.h b/gfx/layers/apz/public/IAPZCTreeManager.h
index 7a6061de38f..512c9af974e 100644
--- a/gfx/layers/apz/public/IAPZCTreeManager.h
+++ b/gfx/layers/apz/public/IAPZCTreeManager.h
@@ -8,6 +8,7 @@
 #include <stdint.h>  // for uint64_t, uint32_t
 
 #include "Units.h"                               // for CSSRect, etc
+#include "mozilla/RefPtr.h"                      // for RefPtr
 #include "mozilla/layers/LayersTypes.h"          // for TouchBehaviorFlags
 #include "mozilla/layers/ScrollableLayerGuid.h"  // for ScrollableLayerGuid, etc
 #include "mozilla/layers/ZoomConstraints.h"      // for ZoomConstraints
@@ -118,12 +119,11 @@ class IAPZCTreeManager {
 
   /**
    * Returns an APZBridge interface that can be used to send input
-   * events to APZ in a synchronous manner. This will always be non-null, and
-   * the returned object's lifetime will match the lifetime of this
-   * IAPZCTreeManager implementation.
+   * events to APZ in a synchronous manner. The returned strong reference keeps
+   * the bridge alive if its owner is destroyed during a synchronous call.
    * It is only valid to call this function in the UI process.
    */
-  virtual APZBridge* Bridge() = 0;
+  virtual RefPtr<APZBridge> Bridge() = 0;
 
  protected:
   // Discourage destruction outside of decref
diff --git a/gfx/layers/apz/src/APZCTreeManager.h b/gfx/layers/apz/src/APZCTreeManager.h
index 64ff3e118b8..c9d92950f0f 100644
--- a/gfx/layers/apz/src/APZCTreeManager.h
+++ b/gfx/layers/apz/src/APZCTreeManager.h
@@ -455,7 +455,7 @@ class APZCTreeManager : public IAPZCTreeManager, public APZBridge {
    */
   bool ChainHasFastPathApzAwareListener(const ScrollableLayerGuid& aHitGuid);
 
-  APZBridge* Bridge() override { return this; }
+  RefPtr<APZBridge> Bridge() override { return this; }
 
   /**
    * Add a callback to be invoked when |aInputBlockId| is ready for handling.
diff --git a/gfx/layers/ipc/APZBridgeChild.cpp b/gfx/layers/ipc/APZBridgeChild.cpp
index 8c5c3135524..39ad6fc6f4d 100644
--- a/gfx/layers/ipc/APZBridgeChild.cpp
+++ b/gfx/layers/ipc/APZBridgeChild.cpp
@@ -104,17 +104,21 @@ void APZBridgeChild::ActorDestroy(ActorDestroyReason aWhy) {
 
 APZEventResult APZBridgeChild::ReceiveInputEvent(
     InputData& aEvent, InputBlockCallback&& aCallback) {
-  MOZ_ASSERT(mIsOpen);
   APZThreadUtils::AssertOnControllerThread();
 
   APZEventResult res;
+  if (!mIsOpen) {
+    return res;
+  }
   switch (aEvent.mInputType) {
     case MULTITOUCH_INPUT: {
       MultiTouchInput& event = aEvent.AsMultiTouchInput();
       MultiTouchInput processedEvent;
 
-      SendReceiveMultiTouchInputEvent(event, !!aCallback, &res,
-                                      &processedEvent);
+      if (!SendReceiveMultiTouchInputEvent(event, !!aCallback, &res,
+                                           &processedEvent)) {
+        return APZEventResult();
+      }
 
       event = std::move(processedEvent);
       break;
@@ -123,7 +127,10 @@ APZEventResult APZBridgeChild::ReceiveInputEvent(
       MouseInput& event = aEvent.AsMouseInput();
       MouseInput processedEvent;
 
-      SendReceiveMouseInputEvent(event, !!aCallback, &res, &processedEvent);
+      if (!SendReceiveMouseInputEvent(event, !!aCallback, &res,
+                                      &processedEvent)) {
+        return APZEventResult();
+      }
 
       event = std::move(processedEvent);
       break;
@@ -132,8 +139,10 @@ APZEventResult APZBridgeChild::ReceiveInputEvent(
       PanGestureInput& event = aEvent.AsPanGestureInput();
       PanGestureInput processedEvent;
 
-      SendReceivePanGestureInputEvent(event, !!aCallback, &res,
-                                      &processedEvent);
+      if (!SendReceivePanGestureInputEvent(event, !!aCallback, &res,
+                                           &processedEvent)) {
+        return APZEventResult();
+      }
 
       event = std::move(processedEvent);
       break;
@@ -142,8 +151,10 @@ APZEventResult APZBridgeChild::ReceiveInputEvent(
       PinchGestureInput& event = aEvent.AsPinchGestureInput();
       PinchGestureInput processedEvent;
 
-      SendReceivePinchGestureInputEvent(event, !!aCallback, &res,
-                                        &processedEvent);
+      if (!SendReceivePinchGestureInputEvent(event, !!aCallback, &res,
+                                             &processedEvent)) {
+        return APZEventResult();
+      }
 
       event = std::move(processedEvent);
       break;
@@ -152,8 +163,10 @@ APZEventResult APZBridgeChild::ReceiveInputEvent(
       TapGestureInput& event = aEvent.AsTapGestureInput();
       TapGestureInput processedEvent;
 
-      SendReceiveTapGestureInputEvent(event, !!aCallback, &res,
-                                      &processedEvent);
+      if (!SendReceiveTapGestureInputEvent(event, !!aCallback, &res,
+                                           &processedEvent)) {
+        return APZEventResult();
+      }
 
       event = std::move(processedEvent);
       break;
@@ -162,8 +175,10 @@ APZEventResult APZBridgeChild::ReceiveInputEvent(
       ScrollWheelInput& event = aEvent.AsScrollWheelInput();
       ScrollWheelInput processedEvent;
 
-      SendReceiveScrollWheelInputEvent(event, !!aCallback, &res,
-                                       &processedEvent);
+      if (!SendReceiveScrollWheelInputEvent(event, !!aCallback, &res,
+                                            &processedEvent)) {
+        return APZEventResult();
+      }
 
       event = std::move(processedEvent);
       break;
@@ -172,7 +187,10 @@ APZEventResult APZBridgeChild::ReceiveInputEvent(
       KeyboardInput& event = aEvent.AsKeyboardInput();
       KeyboardInput processedEvent;
 
-      SendReceiveKeyboardInputEvent(event, !!aCallback, &res, &processedEvent);
+      if (!SendReceiveKeyboardInputEvent(event, !!aCallback, &res,
+                                         &processedEvent)) {
+        return APZEventResult();
+      }
 
       event = std::move(processedEvent);
       break;
@@ -184,7 +202,7 @@ APZEventResult APZBridgeChild::ReceiveInputEvent(
     }
   }
 
-  if (aCallback && res.WillHaveDelayedResult()) {
+  if (mIsOpen && aCallback && res.WillHaveDelayedResult()) {
     mInputBlockCallbacks.emplace(res.mInputBlockId, std::move(aCallback));
   }
 
@@ -334,9 +352,12 @@ void APZBridgeChild::ProcessUnhandledEvent(LayoutDeviceIntPoint* aRefPoint,
                                            ScrollableLayerGuid* aOutTargetGuid,
                                            uint64_t* aOutFocusSequenceNumber,
                                            LayersId* aOutLayersId) {
-  MOZ_ASSERT(mIsOpen);
   APZThreadUtils::AssertOnControllerThread();
 
+  if (!mIsOpen) {
+    return;
+  }
+
   SendProcessUnhandledEvent(*aRefPoint, aRefPoint, aOutTargetGuid,
                             aOutFocusSequenceNumber, aOutLayersId);
 }
@@ -344,9 +365,12 @@ void APZBridgeChild::ProcessUnhandledEvent(LayoutDeviceIntPoint* aRefPoint,
 void APZBridgeChild::UpdateWheelTransaction(
     LayoutDeviceIntPoint aRefPoint, EventMessage aEventMessage,
     const Maybe<ScrollableLayerGuid>& aTargetGuid) {
-  MOZ_ASSERT(mIsOpen);
   APZThreadUtils::AssertOnControllerThread();
 
+  if (!mIsOpen) {
+    return;
+  }
+
   SendUpdateWheelTransaction(aRefPoint, aEventMessage, aTargetGuid);
 }
 
diff --git a/gfx/layers/ipc/APZCTreeManagerChild.cpp b/gfx/layers/ipc/APZCTreeManagerChild.cpp
index 6d819a68c23..176a62e2782 100644
--- a/gfx/layers/ipc/APZCTreeManagerChild.cpp
+++ b/gfx/layers/ipc/APZCTreeManagerChild.cpp
@@ -97,11 +97,11 @@ void APZCTreeManagerChild::NotifyApzAwareListenerAdded(
   }
 }
 
-APZBridge* APZCTreeManagerChild::Bridge() {
+RefPtr<APZBridge> APZCTreeManagerChild::Bridge() {
   MOZ_ASSERT(XRE_IsParentProcess());
   MOZ_ASSERT(mBridge);
 
-  return mBridge.get();
+  return mBridge;
 }
 
 }  // namespace layers
diff --git a/gfx/layers/ipc/APZCTreeManagerChild.h b/gfx/layers/ipc/APZCTreeManagerChild.h
index e91dadac4bc..bd47ddcbcbc 100644
--- a/gfx/layers/ipc/APZCTreeManagerChild.h
+++ b/gfx/layers/ipc/APZCTreeManagerChild.h
@@ -52,7 +52,7 @@ class APZCTreeManagerChild final : public IAPZCTreeManager,
 
   void NotifyApzAwareListenerAdded(const ScrollableLayerGuid& aGuid) override;
 
-  APZBridge* Bridge() override;
+  RefPtr<APZBridge> Bridge() override;
 
  protected:
   virtual ~APZCTreeManagerChild();
diff --git a/gfx/layers/apz/test/gtest/TestAPZBridge.cpp b/gfx/layers/apz/test/gtest/TestAPZBridge.cpp
new file mode 100644
index 00000000000..bca1ce0a448
--- /dev/null
+++ b/gfx/layers/apz/test/gtest/TestAPZBridge.cpp
@@ -0,0 +1,58 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/layers/APZBridgeChild.h"
+#include "mozilla/layers/APZCTreeManagerChild.h"
+#include "mozilla/layers/APZThreadUtils.h"
+#include "nsThreadUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::layers;
+
+namespace {
+
+class DestroyingAPZBridgeChild final : public APZBridgeChild {
+ public:
+  DestroyingAPZBridgeChild(APZCTreeManagerChild& aManager, bool& aIsDestroyed)
+      : APZBridgeChild(0), mManager(aManager), mIsDestroyed(aIsDestroyed) {}
+
+  APZEventResult ReceiveInputEvent(InputData& aEvent,
+                                   InputBlockCallback&& aCallback) override {
+    bool& isDestroyed = mIsDestroyed;
+    mManager.Destroy();
+    EXPECT_FALSE(isDestroyed);
+    return APZEventResult();
+  }
+
+ private:
+  ~DestroyingAPZBridgeChild() override { mIsDestroyed = true; }
+
+  APZCTreeManagerChild& mManager;
+  bool& mIsDestroyed;
+};
+
+class APZBridgeTester : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    APZThreadUtils::SetControllerThread(NS_GetCurrentThread());
+  }
+
+  void TearDown() override { APZThreadUtils::SetControllerThread(nullptr); }
+};
+
+}  // namespace
+
+TEST_F(APZBridgeTester, DestroyOwnerDuringMouseInput) {
+  bool isDestroyed = false;
+  auto manager = MakeRefPtr<APZCTreeManagerChild>();
+  manager->SetBridge(
+      MakeRefPtr<DestroyingAPZBridgeChild>(*manager, isDestroyed));
+
+  WidgetMouseEvent event(true, eMouseMove, nullptr, WidgetMouseEvent::eReal);
+  EXPECT_EQ(manager->Bridge()->ReceiveInputEvent(event).GetStatus(),
+            nsEventStatus_eIgnore);
+  EXPECT_TRUE(isDestroyed);
+}
diff --git a/gfx/layers/apz/test/gtest/moz.build b/gfx/layers/apz/test/gtest/moz.build
index d781ce211e3..e328f36ae0e 100644
--- a/gfx/layers/apz/test/gtest/moz.build
+++ b/gfx/layers/apz/test/gtest/moz.build
@@ -6,6 +6,7 @@ UNIFIED_SOURCES += [
     "APZTestAccess.cpp",
     "APZTestCommon.cpp",
     "MockHitTester.cpp",
+    "TestAPZBridge.cpp",
     "TestAxisLock.cpp",
     "TestBasic.cpp",
     "TestDisplayPort.cpp",

diff --git a/gfx/layers/apz/test/gtest/TestAPZBridge.cpp b/gfx/layers/apz/test/gtest/TestAPZBridge.cpp
new file mode 100644
index 00000000000..bca1ce0a448
--- /dev/null
+++ b/gfx/layers/apz/test/gtest/TestAPZBridge.cpp
@@ -0,0 +1,58 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/layers/APZBridgeChild.h"
+#include "mozilla/layers/APZCTreeManagerChild.h"
+#include "mozilla/layers/APZThreadUtils.h"
+#include "nsThreadUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::layers;
+
+namespace {
+
+class DestroyingAPZBridgeChild final : public APZBridgeChild {
+ public:
+  DestroyingAPZBridgeChild(APZCTreeManagerChild& aManager, bool& aIsDestroyed)
+      : APZBridgeChild(0), mManager(aManager), mIsDestroyed(aIsDestroyed) {}
+
+  APZEventResult ReceiveInputEvent(InputData& aEvent,
+                                   InputBlockCallback&& aCallback) override {
+    bool& isDestroyed = mIsDestroyed;
+    mManager.Destroy();
+    EXPECT_FALSE(isDestroyed);
+    return APZEventResult();
+  }
+
+ private:
+  ~DestroyingAPZBridgeChild() override { mIsDestroyed = true; }
+
+  APZCTreeManagerChild& mManager;
+  bool& mIsDestroyed;
+};
+
+class APZBridgeTester : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    APZThreadUtils::SetControllerThread(NS_GetCurrentThread());
+  }
+
+  void TearDown() override { APZThreadUtils::SetControllerThread(nullptr); }
+};
+
+}  // namespace
+
+TEST_F(APZBridgeTester, DestroyOwnerDuringMouseInput) {
+  bool isDestroyed = false;
+  auto manager = MakeRefPtr<APZCTreeManagerChild>();
+  manager->SetBridge(
+      MakeRefPtr<DestroyingAPZBridgeChild>(*manager, isDestroyed));
+
+  WidgetMouseEvent event(true, eMouseMove, nullptr, WidgetMouseEvent::eReal);
+  EXPECT_EQ(manager->Bridge()->ReceiveInputEvent(event).GetStatus(),
+            nsEventStatus_eIgnore);
+  EXPECT_TRUE(isDestroyed);
+}
diff --git a/gfx/layers/apz/test/gtest/moz.build b/gfx/layers/apz/test/gtest/moz.build
index d781ce211e3..e328f36ae0e 100644
--- a/gfx/layers/apz/test/gtest/moz.build
+++ b/gfx/layers/apz/test/gtest/moz.build
@@ -6,6 +6,7 @@ UNIFIED_SOURCES += [
     "APZTestAccess.cpp",
     "APZTestCommon.cpp",
     "MockHitTester.cpp",
+    "TestAPZBridge.cpp",
     "TestAxisLock.cpp",
     "TestBasic.cpp",
     "TestDisplayPort.cpp",