--- a/gfx/layers/ipc/PWebRenderBridge.ipdl
+++ b/gfx/layers/ipc/PWebRenderBridge.ipdl
@@ -40,17 +40,17 @@ parent:
   sync Create(IntSize aSize);
   sync AddImage(ImageKey aImageKey, IntSize aSize, uint32_t aStride,
                 SurfaceFormat aFormat, ByteBuffer aBytes);
   async AddBlobImage(ImageKey aImageKey, IntSize aSize, uint32_t aStride,
                      SurfaceFormat aFormat, ByteBuffer aBytes);
   sync UpdateImage(ImageKey aImageKey, IntSize aSize,
                    SurfaceFormat aFormat, ByteBuffer aBytes);
   sync DeleteImage(ImageKey aImageKey);
-  async DeleteCompositorAnimations(uint64_t aId);
+  async DeleteCompositorAnimations(uint64_t[] aIds);
   async AddRawFont(FontKey aFontKey, ByteBuffer aBytes, uint32_t aFontIndex);
   async DeleteFont(FontKey aFontKey);
   async DPBegin(IntSize aSize);
   async DPEnd(IntSize aSize, WebRenderParentCommand[] commands, OpDestroy[] toDestroy, uint64_t fwdTransactionId, uint64_t transactionId,
               ByteBuffer aDL, WrBuiltDisplayListDescriptor aDLDesc, ByteBuffer aAux, WrAuxiliaryListsDescriptor aAuxDesc);
   sync DPSyncEnd(IntSize aSize, WebRenderParentCommand[] commands, OpDestroy[] toDestroy, uint64_t fwdTransactionId, uint64_t transactionId,
                  ByteBuffer aDL, WrBuiltDisplayListDescriptor aDLDesc, ByteBuffer aAux, WrAuxiliaryListsDescriptor aAuxDesc);
   sync DPGetSnapshot(PTexture texture);

--- a/gfx/layers/wr/WebRenderBridgeParent.cpp
+++ b/gfx/layers/wr/WebRenderBridgeParent.cpp
@@ -191,17 +191,17 @@ WebRenderBridgeParent::RecvAddImage(cons
   mApi->AddImage(aImageKey, descriptor,
                  aBuffer.AsSlice());
 
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult
 WebRenderBridgeParent::RecvAddBlobImage(const wr::ImageKey& aImageKey,
-                        				        const gfx::IntSize& aSize,
+                                        const gfx::IntSize& aSize,
                                         const uint32_t& aStride,
                                         const gfx::SurfaceFormat& aFormat,
                                         const ByteBuffer& aBuffer)
 {
   if (mDestroyed) {
     return IPC_OK();
   }
   MOZ_ASSERT(mApi);
@@ -264,27 +264,30 @@ WebRenderBridgeParent::RecvDeleteImage(c
   if (mActiveKeys.Get(wr::AsUint64(aImageKey), nullptr)) {
     mActiveKeys.Remove(wr::AsUint64(aImageKey));
   }
   mKeysToDelete.push_back(aImageKey);
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult
-WebRenderBridgeParent::RecvDeleteCompositorAnimations(const uint64_t& aId)
+WebRenderBridgeParent::RecvDeleteCompositorAnimations(InfallibleTArray<uint64_t>&& aIds)
 {
   if (mDestroyed) {
     return IPC_OK();
   }
-  uint64_t id = mWidget ? 0 : mPipelineId.mHandle;
+
+  uint64_t storageId = mWidget ? 0 : mPipelineId.mHandle;
   CompositorAnimationStorage* storage =
-    mCompositorBridge->GetAnimationStorage(id);
+    mCompositorBridge->GetAnimationStorage(storageId);
+  MOZ_ASSERT(storage);
 
-  MOZ_ASSERT(storage);
-  storage->ClearById(aId);
+  for (uint32_t i=0; i < aIds.Length(); i++) {
+    storage->ClearById(aIds[i]);
+  }
 
   return IPC_OK();
 }
 
 
 mozilla::ipc::IPCResult
 WebRenderBridgeParent::RecvDPBegin(const gfx::IntSize& aSize)
 {

--- a/gfx/layers/wr/WebRenderBridgeParent.h
+++ b/gfx/layers/wr/WebRenderBridgeParent.h
@@ -73,17 +73,17 @@ public:
                                            const uint32_t& aStride,
                                            const gfx::SurfaceFormat& aFormat,
                                            const ByteBuffer& aBuffer) override;
   mozilla::ipc::IPCResult RecvUpdateImage(const wr::ImageKey& aImageKey,
                                           const gfx::IntSize& aSize,
                                           const gfx::SurfaceFormat& aFormat,
                                           const ByteBuffer& aBuffer) override;
   mozilla::ipc::IPCResult RecvDeleteImage(const wr::ImageKey& a1) override;
-  mozilla::ipc::IPCResult RecvDeleteCompositorAnimations(const uint64_t& aId) override;
+  mozilla::ipc::IPCResult RecvDeleteCompositorAnimations(InfallibleTArray<uint64_t>&& aIds) override;
   mozilla::ipc::IPCResult RecvAddRawFont(const wr::FontKey& aFontKey,
                                          const ByteBuffer& aBuffer,
                                          const uint32_t& aFontIndex) override;
   mozilla::ipc::IPCResult RecvDeleteFont(const wr::FontKey& aFontKey) override;
   mozilla::ipc::IPCResult RecvDPBegin(const gfx::IntSize& aSize) override;
   mozilla::ipc::IPCResult RecvDPEnd(const gfx::IntSize& aSize,
                                     InfallibleTArray<WebRenderParentCommand>&& aCommands,
                                     InfallibleTArray<OpDestroy>&& aToDestroy,

--- a/gfx/layers/wr/WebRenderLayerManager.cpp
+++ b/gfx/layers/wr/WebRenderLayerManager.cpp
@@ -454,26 +454,27 @@ WebRenderLayerManager::DiscardImages()
       WrBridge()->SendDeleteImage(key);
   }
   mImageKeys.clear();
 }
 
 void
 WebRenderLayerManager::AddCompositorAnimationsIdForDiscard(uint64_t aId)
 {
-  mDiscardedCompositorAnimationsIds.push_back(aId);
+  mDiscardedCompositorAnimationsIds.AppendElement(aId);
 }
 
 void
 WebRenderLayerManager::DiscardCompositorAnimations()
 {
-  for (auto id : mDiscardedCompositorAnimationsIds) {
-    WrBridge()->SendDeleteCompositorAnimations(id);
+  if (!mDiscardedCompositorAnimationsIds.IsEmpty()) {
+    WrBridge()->
+      SendDeleteCompositorAnimations(mDiscardedCompositorAnimationsIds);
+    mDiscardedCompositorAnimationsIds.Clear();
   }
-  mDiscardedCompositorAnimationsIds.clear();
 }
 
 
 void
 WebRenderLayerManager::Hold(Layer* aLayer)
 {
   mKeepAlive.AppendElement(aLayer);
 }

--- a/gfx/layers/wr/WebRenderLayerManager.h
+++ b/gfx/layers/wr/WebRenderLayerManager.h
@@ -171,17 +171,17 @@ private:
    */
   void MakeSnapshotIfRequired(LayoutDeviceIntSize aSize);
 
   void ClearLayer(Layer* aLayer);
 
 private:
   nsIWidget* MOZ_NON_OWNING_REF mWidget;
   std::vector<wr::ImageKey> mImageKeys;
-  std::vector<uint64_t> mDiscardedCompositorAnimationsIds;
+  nsTArray<uint64_t> mDiscardedCompositorAnimationsIds;
 
   /* PaintedLayer callbacks; valid at the end of a transaciton,
    * while rendering */
   DrawPaintedLayerCallback mPaintedLayerCallback;
   void *mPaintedLayerCallbackData;
 
   RefPtr<WebRenderBridgeChild> mWrChild;