diff --git a/engine/src/flutter/compositor/surface_allocator.cc b/engine/src/flutter/compositor/surface_allocator.cc
index 80cc7a1e1d..7b3d381b41 100644
--- a/engine/src/flutter/compositor/surface_allocator.cc
+++ b/engine/src/flutter/compositor/surface_allocator.cc
@@ -16,13 +16,11 @@ SurfaceAllocator::SurfaceAllocator(uint32_t id_namespace)
 SurfaceAllocator::~SurfaceAllocator() {
 }
 
-uint64_t SurfaceAllocator::CreateSurfaceId() {
-  // Surface IDs are 64 integers. The high 32 bits are the namespace of the ID,
-  // which is assigned to us by the surfaces service. The lower 32 bits are ours
-  // to allocate as we see fit. For simplicity, we just allocate them
-  // sequentially. In principle, we could run out, but at 60 Hz, it takes
-  // several years to run out.
-  return static_cast<uint64_t>(id_namespace_) << 32 | next_id_++;
+mojo::SurfaceIdPtr SurfaceAllocator::CreateSurfaceId() {
+  auto id = mojo::SurfaceId::New();
+  id->local = next_id_++;
+  id->id_namespace = id_namespace_;
+  return id.Pass();
 }
 
 }  // namespace sky
diff --git a/engine/src/flutter/compositor/surface_allocator.h b/engine/src/flutter/compositor/surface_allocator.h
index 98feb1118a..5da7c6f11e 100644
--- a/engine/src/flutter/compositor/surface_allocator.h
+++ b/engine/src/flutter/compositor/surface_allocator.h
@@ -6,6 +6,7 @@
 #define SKY_COMPOSITOR_SURFACE_ALLOCATOR_H_
 
 #include "base/basictypes.h"
+#include "mojo/services/surfaces/public/interfaces/surface_id.mojom.h"
 
 namespace sky {
 
@@ -14,7 +15,7 @@ class SurfaceAllocator {
   SurfaceAllocator(uint32_t id_namespace);
   ~SurfaceAllocator();
 
-  uint64_t CreateSurfaceId();
+  mojo::SurfaceIdPtr CreateSurfaceId();
 
  private:
   uint32_t id_namespace_;
diff --git a/engine/src/flutter/compositor/surface_holder.cc b/engine/src/flutter/compositor/surface_holder.cc
index 26d2098c96..e8475802f3 100644
--- a/engine/src/flutter/compositor/surface_holder.cc
+++ b/engine/src/flutter/compositor/surface_holder.cc
@@ -51,13 +51,16 @@ void SurfaceHolder::SetSize(const gfx::Size& size) {
     surface_id_ = mojo::SurfaceId::New();
   }
 
-  surface_id_->id = surface_allocator_->CreateSurfaceId();
-  surface_->CreateSurface(surface_id_.Clone(), mojo::Size::From(size));
+  surface_id_ = surface_allocator_->CreateSurfaceId();
+  surface_->CreateSurface(surface_id_.Clone());
   size_ = size;
 
   client_->OnSurfaceIdAvailable(surface_id_.Clone());
 }
 
+void SurfaceHolder::SetIdNamespace(uint32_t id_namespace) {
+}
+
 void SurfaceHolder::ReturnResources(
     mojo::Array<mojo::ReturnedResourcePtr> resources) {
   // TODO(abarth): The surface service shouldn't spam us with empty calls.
diff --git a/engine/src/flutter/compositor/surface_holder.h b/engine/src/flutter/compositor/surface_holder.h
index e33bce31c9..9bf5ad25f4 100644
--- a/engine/src/flutter/compositor/surface_holder.h
+++ b/engine/src/flutter/compositor/surface_holder.h
@@ -43,6 +43,7 @@ class SurfaceHolder : public mojo::SurfaceClient {
 
  private:
   // mojo::SurfaceClient
+  void SetIdNamespace(uint32_t id_namespace) override;
   void ReturnResources(
       mojo::Array<mojo::ReturnedResourcePtr> resources) override;