mozart: Port the spinning cube example.

mojo/gpu/texture_cache.cc

Index: mojo/gpu/texture_cache.cc
diff --git a/mojo/gpu/texture_cache.cc b/mojo/gpu/texture_cache.cc
index f97a2ed085051fd05106418b6e0d16f9ea41aa5d..a76fedbacf55b50503904691be5cd2d10aac9fa7 100644
--- a/mojo/gpu/texture_cache.cc
+++ b/mojo/gpu/texture_cache.cc
@@ -56,6 +56,7 @@ scoped_ptr<TextureCache::TextureInfo> TextureCache::GetTexture(
     // If the texture is the right size, use it.
     if (texture_size.width == requested_size.width &&
         texture_size.height == requested_size.height) {
+      gl_context_->MakeCurrent();
       glWaitSyncPointCHROMIUM(sync_point);
       return texture_info;
     }