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

ui/ozone/platform/caca/ozone_platform_caca.cc

Index: ui/ozone/platform/caca/ozone_platform_caca.cc
diff --git a/ui/ozone/platform/caca/ozone_platform_caca.cc b/ui/ozone/platform/caca/ozone_platform_caca.cc
index 16adec8ecb8825e9f06fee47b2d7d1110c82d4e7..3a27b4434e3f486f65d76511163a5a3e397d1978 100644
--- a/ui/ozone/platform/caca/ozone_platform_caca.cc
+++ b/ui/ozone/platform/caca/ozone_platform_caca.cc
@@ -34,6 +34,12 @@ class OzonePlatformCaca : 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()