# HG changeset patch
# User sotaro <sotaro.ikeda.g@gmail.com>
# Date 1520916787 -32400
# Node ID b821737a49f966403c2cff7c4a4a302dc787c5af
# Parent  2bca446bdc22dc4944face48a75202a308e221a2
Bug 1426588 - Add more check to CrossProcessCompositorBridgeParent::AllocPWebRenderBridgeParent() r=nical

diff --git a/gfx/layers/ipc/CrossProcessCompositorBridgeParent.cpp b/gfx/layers/ipc/CrossProcessCompositorBridgeParent.cpp
--- a/gfx/layers/ipc/CrossProcessCompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/CrossProcessCompositorBridgeParent.cpp
@@ -211,28 +211,33 @@ CrossProcessCompositorBridgeParent::Allo
   MOZ_ASSERT(sIndirectLayerTrees.find(layersId) != sIndirectLayerTrees.end());
   MOZ_ASSERT(sIndirectLayerTrees[layersId].mWrBridge == nullptr);
   WebRenderBridgeParent* parent = nullptr;
   WebRenderBridgeParent* root = nullptr;
   CompositorBridgeParent* cbp = sIndirectLayerTrees[layersId].mParent;
   if (cbp) {
     root = sIndirectLayerTrees[cbp->RootLayerTreeId()].mWrBridge.get();
   }
-  if (!root) {
+
+  RefPtr<wr::WebRenderAPI> api;
+  if (root) {
+    api = root->GetWebRenderAPI();
+  }
+
+  if (!root || !api) {
     // This could happen when this function is called after CompositorBridgeParent destruction.
     // This was observed during Tab move between different windows.
-    NS_WARNING("Created child without a matching parent?");
+    NS_WARNING(nsPrintfCString("Created child without a matching parent? root %p", root).get());
     parent = WebRenderBridgeParent::CreateDestroyed(aPipelineId);
     parent->AddRef(); // IPDL reference
     *aIdNamespace = parent->GetIdNamespace();
     *aTextureFactoryIdentifier = TextureFactoryIdentifier(LayersBackend::LAYERS_NONE);
     return parent;
   }
 
-  RefPtr<wr::WebRenderAPI> api = root->GetWebRenderAPI();
   api = api->Clone();
   RefPtr<AsyncImagePipelineManager> holder = root->AsyncImageManager();
   RefPtr<CompositorAnimationStorage> animStorage = cbp->GetAnimationStorage();
   parent = new WebRenderBridgeParent(this, aPipelineId, nullptr, root->CompositorScheduler(), Move(api), Move(holder), Move(animStorage));
   parent->AddRef(); // IPDL reference
 
   sIndirectLayerTrees[layersId].mCrossProcessParent = this;
   sIndirectLayerTrees[layersId].mWrBridge = parent;