Bug 1251807 - Use the surface's size, not the intrinsic size, in CopyFrame. r=tn

    return nullptr;

  }

  // Create a 32-bit image surface of our size, but draw using the frame's

  // rect, implicitly padding the frame out to the image's size.

  IntSize size(mSize.width, mSize.height);

  // Create a 32-bit surface at the decoded size of the image. If

  // FLAG_SYNC_DECODE was not passed, we may have substituted a downscaled

  // version of the image we already had available, so this is not necessarily

  // the intrinsic size of the image. We'll take the frame rect of the image

  // into account when we draw, implicitly adding padding so that the caller

  // doesn't need to worry about frame rects.

  // XXX(seth): In bug 1247520 we'll remove support for frame rects, rendering

  // this additional padding unnecessary.

  RefPtr<DataSourceSurface> surf =

    Factory::CreateDataSourceSurface(size,

    Factory::CreateDataSourceSurface(frameRef->GetImageSize(),

                                     SurfaceFormat::B8G8R8A8,

                                     /* aZero = */ true);

  if (NS_WARN_IF(!surf)) {

  RefPtr<DrawTarget> target =

    Factory::CreateDrawTargetForData(BackendType::CAIRO,

                                     mapping.mData,

                                     size,

                                     frameRef->GetImageSize(),

                                     mapping.mStride,

                                     SurfaceFormat::B8G8R8A8);

  if (!target) {