TextureClient*
PersistentBufferProviderShared::GetTextureClient()
{
  // Can't access the front buffer while drawing.
  MOZ_ASSERT(!mDrawTarget);
  TextureClient* texture = GetTexture(mFront);
  if (texture) {
    texture->EnableReadLock();
  } else {
    gfxCriticalNote << "PersistentBufferProviderShared: front buffer unavailable";
  }
  return texture;
}