mozart: Port the spinning cube example.

mojo/gpu/texture_cache.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef GL_GLEXT_PROTOTYPES
 #define GL_GLEXT_PROTOTYPES
 #endif
 #include <GLES2/gl2extmojo.h>
 
 #include "mojo/gpu/gl_context.h"
@@ skipping 38 matching lines @@
 
     // Get the sync point from the sync point map.
     auto sync_point_iterator =
         resource_to_sync_point_map_.find(available_resource_id);
     int sync_point = sync_point_iterator->second;
     resource_to_sync_point_map_.erase(sync_point_iterator);
 
     // 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;
     }
   }
 
   // If our context is invalid return an empty scoped ptr.
   if (!gl_context_) {
     return scoped_ptr<TextureInfo>();
   }
 
@@ skipping 25 matching lines @@
     auto it = resource_to_texture_map_.find(resource->id);
     // Ignore the returned resource if we haven't been notified of its pending
     // return.
     if (it != resource_to_texture_map_.end()) {
       available_textures_.push_back(resource->id);
       resource_to_sync_point_map_[resource->id] = resource->sync_point;
     }
   }
 }
 }  // namespace mojo