sync compositor: pass simple gfx types by const ref

See bug for reasoning

BUG=159273

Review URL: https://codereview.chromium.org/1417893006

Cr-Commit-Position: refs/heads/master@{#356653}
void SynchronousCompositorImpl::UpdateRootLayerState(
    const gfx::ScrollOffset& total_scroll_offset,
    const gfx::ScrollOffset& max_scroll_offset,
    const gfx::SizeF& scrollable_size,
    float page_scale_factor,
    float min_page_scale_factor,
    float max_page_scale_factor) {
  DCHECK(CalledOnValidThread());

  if (registered_with_client_) {
    compositor_client_->UpdateRootLayerState(
        gfx::ScrollOffsetToVector2dF(total_scroll_offset),
        gfx::ScrollOffsetToVector2dF(max_scroll_offset),
        scrollable_size,
        page_scale_factor,
        min_page_scale_factor,
        max_page_scale_factor);
  }
}

void SynchronousCompositorImpl::UpdateRootLayerState(
    const gfx::ScrollOffset& total_scroll_offset,
    const gfx::ScrollOffset& max_scroll_offset,
    const gfx::SizeF& scrollable_size,
    float page_scale_factor,
    float min_page_scale_factor,
    float max_page_scale_factor) {
  DCHECK(CalledOnValidThread());

  if (registered_with_client_) {
    compositor_client_->UpdateRootLayerState(
        gfx::ScrollOffsetToVector2dF(total_scroll_offset),
        gfx::ScrollOffsetToVector2dF(max_scroll_offset),
        scrollable_size,
        page_scale_factor,
        min_page_scale_factor,
        max_page_scale_factor);
  }
}
