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

ui/ozone/platform/test/ozone_platform_test.cc

Index: ui/ozone/platform/test/ozone_platform_test.cc
diff --git a/ui/ozone/platform/test/ozone_platform_test.cc b/ui/ozone/platform/test/ozone_platform_test.cc
index d655fa706b955e399b2188f4a76fa5121260aa8a..27d3d9cbc7deaee13e99475074231528336c0773 100644
--- a/ui/ozone/platform/test/ozone_platform_test.cc
+++ b/ui/ozone/platform/test/ozone_platform_test.cc
@@ -40,6 +40,12 @@ class OzonePlatformTest : 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()