--- a/gfx/layers/ipc/CompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/CompositorBridgeParent.cpp
@@ -173,39 +173,72 @@ CompositorBridgeParentBase::AllocUnsafeS
 }
 
 void
 CompositorBridgeParentBase::DeallocShmem(ipc::Shmem& aShmem)
 {
   PCompositorBridgeParent::DeallocShmem(aShmem);
 }
 
+static inline MessageLoop*
+CompositorLoop()
+{
+  return CompositorThreadHolder::Loop();
+}
+
 base::ProcessId
 CompositorBridgeParentBase::RemotePid()
 {
   return OtherPid();
 }
 
 bool
 CompositorBridgeParentBase::StartSharingMetrics(ipc::SharedMemoryBasic::Handle aHandle,
                                                 CrossProcessMutexHandle aMutexHandle,
                                                 LayersId aLayersId,
                                                 uint32_t aApzcId)
 {
+  if (!CompositorThreadHolder::IsInCompositorThread()) {
+    MOZ_ASSERT(CompositorLoop());
+    CompositorLoop()->PostTask(
+      NewRunnableMethod<ipc::SharedMemoryBasic::Handle,
+                        CrossProcessMutexHandle,
+                        LayersId,
+                        uint32_t>(
+        "layers::CompositorBridgeParent::StartSharingMetrics",
+        this,
+        &CompositorBridgeParentBase::StartSharingMetrics,
+        aHandle, aMutexHandle, aLayersId, aApzcId));
+    return true;
+  }
+
+  MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
   if (!mCanSend) {
     return false;
   }
   return PCompositorBridgeParent::SendSharedCompositorFrameMetrics(
     aHandle, aMutexHandle, aLayersId, aApzcId);
 }
 
 bool
 CompositorBridgeParentBase::StopSharingMetrics(FrameMetrics::ViewID aScrollId,
                                                uint32_t aApzcId)
 {
+  if (!CompositorThreadHolder::IsInCompositorThread()) {
+    MOZ_ASSERT(CompositorLoop());
+    CompositorLoop()->PostTask(
+      NewRunnableMethod<FrameMetrics::ViewID, uint32_t>(
+        "layers::CompositorBridgeParent::StopSharingMetrics",
+        this,
+        &CompositorBridgeParentBase::StopSharingMetrics,
+        aScrollId, aApzcId));
+    return true;
+  }
+
+  MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
   if (!mCanSend) {
     return false;
   }
   return PCompositorBridgeParent::SendReleaseSharedCompositorFrameMetrics(
     aScrollId, aApzcId);
 }
 
 CompositorBridgeParent::LayerTreeState::LayerTreeState()
@@ -308,22 +341,16 @@ CalculateCompositionFrameRate()
       return defaultFrameRate;
     }
     return layoutFrameRatePref;
   }
   return compositionFrameRatePref;
 }
 #endif
 
-static inline MessageLoop*
-CompositorLoop()
-{
-  return CompositorThreadHolder::Loop();
-}
-
 CompositorBridgeParent::CompositorBridgeParent(CompositorManagerParent* aManager,
                                                CSSToLayoutDeviceScale aScale,
                                                const TimeDuration& aVsyncRate,
                                                const CompositorOptions& aOptions,
                                                bool aUseExternalSurfaceSize,
                                                const gfx::IntSize& aSurfaceSize)
   : CompositorBridgeParentBase(aManager)
   , mWidget(nullptr)