diff --git a/cc/output/delegating_renderer.cc b/cc/output/delegating_renderer.cc
index c76f250..7a0eb88 100644
--- a/cc/output/delegating_renderer.cc
+++ b/cc/output/delegating_renderer.cc
@@ -80,7 +80,7 @@
 
 DelegatingRenderer::~DelegatingRenderer() {}
 
-const RendererCapabilities& DelegatingRenderer::Capabilities() const {
+const RendererCapabilitiesImpl& DelegatingRenderer::Capabilities() const {
   return capabilities_;
 }
 
diff --git a/cc/output/delegating_renderer.h b/cc/output/delegating_renderer.h
index c18bfa7..beed12f 100644
--- a/cc/output/delegating_renderer.h
+++ b/cc/output/delegating_renderer.h
@@ -24,7 +24,7 @@
       ResourceProvider* resource_provider);
   virtual ~DelegatingRenderer();
 
-  virtual const RendererCapabilities& Capabilities() const OVERRIDE;
+  virtual const RendererCapabilitiesImpl& Capabilities() const OVERRIDE;
 
   virtual bool CanReadPixels() const OVERRIDE;
 
@@ -60,7 +60,7 @@
 
   OutputSurface* output_surface_;
   ResourceProvider* resource_provider_;
-  RendererCapabilities capabilities_;
+  RendererCapabilitiesImpl capabilities_;
   scoped_ptr<DelegatedFrameData> delegated_frame_data_;
   bool visible_;
 
diff --git a/cc/output/gl_renderer.cc b/cc/output/gl_renderer.cc
index 04db7b0..3bfcae4 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -222,7 +222,7 @@
   CleanupSharedObjects();
 }
 
-const RendererCapabilities& GLRenderer::Capabilities() const {
+const RendererCapabilitiesImpl& GLRenderer::Capabilities() const {
   return capabilities_;
 }
 
diff --git a/cc/output/gl_renderer.h b/cc/output/gl_renderer.h
index cf672f0..ab95931 100644
--- a/cc/output/gl_renderer.h
+++ b/cc/output/gl_renderer.h
@@ -56,7 +56,7 @@
 
   virtual ~GLRenderer();
 
-  virtual const RendererCapabilities& Capabilities() const OVERRIDE;
+  virtual const RendererCapabilitiesImpl& Capabilities() const OVERRIDE;
 
   blink::WebGraphicsContext3D* Context();
 
@@ -223,7 +223,7 @@
   virtual void EnsureBackbuffer() OVERRIDE;
   void EnforceMemoryPolicy();
 
-  RendererCapabilities capabilities_;
+  RendererCapabilitiesImpl capabilities_;
 
   unsigned offscreen_framebuffer_id_;
 
diff --git a/cc/output/renderer.cc b/cc/output/renderer.cc
index 2fe0ef7..488039a 100644
--- a/cc/output/renderer.cc
+++ b/cc/output/renderer.cc
@@ -14,4 +14,26 @@
   return false;
 }
 
+RendererCapabilitiesImpl::RendererCapabilitiesImpl()
+    : best_texture_format(RGBA_8888),
+      allow_partial_texture_updates(false),
+      using_offscreen_context3d(false),
+      max_texture_size(0),
+      using_shared_memory_resources(false),
+      using_partial_swap(false),
+      using_egl_image(false),
+      avoid_pow2_textures(false),
+      using_map_image(false),
+      using_discard_framebuffer(false) {}
+
+RendererCapabilitiesImpl::~RendererCapabilitiesImpl() {}
+
+RendererCapabilities RendererCapabilitiesImpl::MainThreadCapabilities() const {
+  return RendererCapabilities(best_texture_format,
+                              allow_partial_texture_updates,
+                              using_offscreen_context3d,
+                              max_texture_size,
+                              using_shared_memory_resources);
+}
+
 }  // namespace cc
diff --git a/cc/output/renderer.h b/cc/output/renderer.h
index 147b535f..a907cee 100644
--- a/cc/output/renderer.h
+++ b/cc/output/renderer.h
@@ -16,6 +16,27 @@
 class CompositorFrameMetadata;
 class ScopedResource;
 
+struct RendererCapabilitiesImpl {
+  RendererCapabilitiesImpl();
+  ~RendererCapabilitiesImpl();
+
+  // Capabilities copied to main thread.
+  ResourceFormat best_texture_format;
+  bool allow_partial_texture_updates;
+  bool using_offscreen_context3d;
+  int max_texture_size;
+  bool using_shared_memory_resources;
+
+  // Capabilities used on compositor thread only.
+  bool using_partial_swap;
+  bool using_egl_image;
+  bool avoid_pow2_textures;
+  bool using_map_image;
+  bool using_discard_framebuffer;
+
+  RendererCapabilities MainThreadCapabilities() const;
+};
+
 class CC_EXPORT RendererClient {
  public:
   virtual void SetFullRootLayerDamage() = 0;
@@ -25,7 +46,7 @@
  public:
   virtual ~Renderer() {}
 
-  virtual const RendererCapabilities& Capabilities() const = 0;
+  virtual const RendererCapabilitiesImpl& Capabilities() const = 0;
 
   virtual bool CanReadPixels() const = 0;
 
diff --git a/cc/output/software_renderer.cc b/cc/output/software_renderer.cc
index 421e541..596f513 100644
--- a/cc/output/software_renderer.cc
+++ b/cc/output/software_renderer.cc
@@ -96,7 +96,7 @@
 
 SoftwareRenderer::~SoftwareRenderer() {}
 
-const RendererCapabilities& SoftwareRenderer::Capabilities() const {
+const RendererCapabilitiesImpl& SoftwareRenderer::Capabilities() const {
   return capabilities_;
 }
 
diff --git a/cc/output/software_renderer.h b/cc/output/software_renderer.h
index 18fb2a3..aa29274 100644
--- a/cc/output/software_renderer.h
+++ b/cc/output/software_renderer.h
@@ -34,7 +34,7 @@
       ResourceProvider* resource_provider);
 
   virtual ~SoftwareRenderer();
-  virtual const RendererCapabilities& Capabilities() const OVERRIDE;
+  virtual const RendererCapabilitiesImpl& Capabilities() const OVERRIDE;
   virtual void Finish() OVERRIDE;
   virtual void SwapBuffers(const CompositorFrameMetadata& metadata) OVERRIDE;
   virtual void GetFramebufferPixels(void* pixels, gfx::Rect rect) OVERRIDE;
@@ -97,7 +97,7 @@
   void DrawUnsupportedQuad(const DrawingFrame* frame,
                            const DrawQuad* quad);
 
-  RendererCapabilities capabilities_;
+  RendererCapabilitiesImpl capabilities_;
   bool visible_;
   bool is_scissor_enabled_;
   bool is_backbuffer_discarded_;
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index 7432197..bc0029d 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -47,17 +47,23 @@
 
 namespace cc {
 
+RendererCapabilities::RendererCapabilities(ResourceFormat best_texture_format,
+                                           bool allow_partial_texture_updates,
+                                           bool using_offscreen_context3d,
+                                           int max_texture_size,
+                                           bool using_shared_memory_resources)
+    : best_texture_format(best_texture_format),
+      allow_partial_texture_updates(allow_partial_texture_updates),
+      using_offscreen_context3d(using_offscreen_context3d),
+      max_texture_size(max_texture_size),
+      using_shared_memory_resources(using_shared_memory_resources) {}
+
 RendererCapabilities::RendererCapabilities()
     : best_texture_format(RGBA_8888),
-      using_partial_swap(false),
-      using_egl_image(false),
       allow_partial_texture_updates(false),
       using_offscreen_context3d(false),
       max_texture_size(0),
-      avoid_pow2_textures(false),
-      using_map_image(false),
-      using_shared_memory_resources(false),
-      using_discard_framebuffer(false) {}
+      using_shared_memory_resources(false) {}
 
 RendererCapabilities::~RendererCapabilities() {}
 
diff --git a/cc/trees/layer_tree_host.h b/cc/trees/layer_tree_host.h
index 8b9c1cf..3f9e345 100644
--- a/cc/trees/layer_tree_host.h
+++ b/cc/trees/layer_tree_host.h
@@ -64,19 +64,21 @@
 // Provides information on an Impl's rendering capabilities back to the
 // LayerTreeHost.
 struct CC_EXPORT RendererCapabilities {
+  RendererCapabilities(ResourceFormat best_texture_format,
+                       bool allow_partial_texture_updates,
+                       bool using_offscreen_context3d,
+                       int max_texture_size,
+                       bool using_shared_memory_resources);
+
   RendererCapabilities();
   ~RendererCapabilities();
 
+  // Duplicate any modification to this list to RendererCapabilitiesImpl.
   ResourceFormat best_texture_format;
-  bool using_partial_swap;
-  bool using_egl_image;
   bool allow_partial_texture_updates;
   bool using_offscreen_context3d;
   int max_texture_size;
-  bool avoid_pow2_textures;
-  bool using_map_image;
   bool using_shared_memory_resources;
-  bool using_discard_framebuffer;
 };
 
 class CC_EXPORT LayerTreeHost {
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 57928bc..818c2ff 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -1446,7 +1446,8 @@
   return renderer_ && renderer_->IsContextLost();
 }
 
-const RendererCapabilities& LayerTreeHostImpl::GetRendererCapabilities() const {
+const RendererCapabilitiesImpl&
+LayerTreeHostImpl::GetRendererCapabilities() const {
   return renderer_->Capabilities();
 }
 
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index 531384f..f705a66 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -53,7 +53,7 @@
 class TopControlsManager;
 class UIResourceBitmap;
 class UIResourceRequest;
-struct RendererCapabilities;
+struct RendererCapabilitiesImpl;
 
 // LayerTreeHost->Proxy callback interface.
 class LayerTreeHostImplClient {
@@ -257,7 +257,7 @@
   bool IsContextLost();
   TileManager* tile_manager() { return tile_manager_.get(); }
   Renderer* renderer() { return renderer_.get(); }
-  const RendererCapabilities& GetRendererCapabilities() const;
+  const RendererCapabilitiesImpl& GetRendererCapabilities() const;
 
   virtual bool SwapBuffers(const FrameData& frame);
   void SetNeedsBeginImplFrame(bool enable);
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index 9f181cd..3f7b4c6 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -517,7 +517,7 @@
   return layer_tree_host_impl_->settings();
 }
 
-const RendererCapabilities& LayerTreeImpl::GetRendererCapabilities() const {
+const RendererCapabilitiesImpl& LayerTreeImpl::GetRendererCapabilities() const {
   return layer_tree_host_impl_->GetRendererCapabilities();
 }
 
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index 2f27460..7c4479d 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -14,6 +14,7 @@
 #include "cc/base/scoped_ptr_vector.h"
 #include "cc/base/swap_promise.h"
 #include "cc/layers/layer_impl.h"
+#include "cc/output/renderer.h"
 #include "cc/resources/ui_resource_client.h"
 
 #if defined(COMPILER_GCC)
@@ -59,7 +60,7 @@
   // Methods called by the layer tree that pass-through or access LTHI.
   // ---------------------------------------------------------------------------
   const LayerTreeSettings& settings() const;
-  const RendererCapabilities& GetRendererCapabilities() const;
+  const RendererCapabilitiesImpl& GetRendererCapabilities() const;
   ContextProvider* context_provider() const;
   OutputSurface* output_surface() const;
   ResourceProvider* resource_provider() const;
diff --git a/cc/trees/single_thread_proxy.cc b/cc/trees/single_thread_proxy.cc
index f1f8a4f..a313588 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -148,7 +148,8 @@
         output_surface.Pass());
     if (initialized) {
       renderer_capabilities_for_main_thread_ =
-          layer_tree_host_impl_->GetRendererCapabilities();
+          layer_tree_host_impl_->GetRendererCapabilities()
+              .MainThreadCapabilities();
     } else if (offscreen_context_provider.get()) {
       offscreen_context_provider->VerifyContexts();
       offscreen_context_provider = NULL;
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index 2823182..62e0ca2 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -1427,7 +1427,8 @@
   *success = layer_tree_host_impl_->InitializeRenderer(output_surface.Pass());
 
   if (*success) {
-    *capabilities = layer_tree_host_impl_->GetRendererCapabilities();
+    *capabilities = layer_tree_host_impl_->GetRendererCapabilities()
+                        .MainThreadCapabilities();
     scheduler_on_impl_thread_->DidCreateAndInitializeOutputSurface();
   } else if (offscreen_context_provider.get()) {
     if (offscreen_context_provider->BindToCurrentThread())