ozone: gpu: Add plumbing for platform-specific gpu messaging

ui/ozone/platform/dri/ozone_platform_dri.cc

Index: ui/ozone/platform/dri/ozone_platform_dri.cc
diff --git a/ui/ozone/platform/dri/ozone_platform_dri.cc b/ui/ozone/platform/dri/ozone_platform_dri.cc
index 4d77c35129d244669c7abd82e74952b60a42abcf..ffd4bef780dc4cd286944784e052637425db9a5a 100644
--- a/ui/ozone/platform/dri/ozone_platform_dri.cc
+++ b/ui/ozone/platform/dri/ozone_platform_dri.cc
@@ -71,6 +71,12 @@ class OzonePlatformDri : public OzonePlatform {
   virtual CursorFactoryOzone* GetCursorFactoryOzone() OVERRIDE {
     return cursor_factory_ozone_.get();
   }
+  virtual GpuPlatformSupport* GetGpuPlatformSupport() OVERRIDE {
+    return NULL;  // no GPU support
+  }
+  virtual GpuPlatformSupportHost* GetGpuPlatformSupportHost() OVERRIDE {
+    return NULL;  // no GPU support
+  }
 #if defined(OS_CHROMEOS)
   virtual scoped_ptr<NativeDisplayDelegate> CreateNativeDisplayDelegate()
       OVERRIDE {