Bug 974356 - 3/4 - Make TextureHost::CreateIPDLActor check for bad MemoryTextures - r=nical

gfx/layers/composite/TextureHost.cpp

@@ -61,6 +61,12 @@ TextureHost::CreateIPDLActor(ISurfaceAllocator* aAllocator,
                              const SurfaceDescriptor& aSharedData,
                              TextureFlags aFlags)
 {
+  if (aSharedData.type() == SurfaceDescriptor::TSurfaceDescriptorMemory &&
+      !aAllocator->IsSameProcess())
+  {
+    NS_ERROR("A client process is trying to peek at our address space using a MemoryTexture!");
+    return nullptr;
+  }
   TextureParent* actor = new TextureParent(aAllocator);
   DebugOnly<bool> status = actor->Init(aSharedData, aFlags);
   MOZ_ASSERT(status);