Use the host coordinate when comparing to host window bounds.

I somehow overlooked this and the test was not strict enough to catch this.

BUG=521919
TEST=Updated ScreenPositionControllerTest.ConvertHostPointToScreenHiDPI so that it fails without the patch.

Review URL: https://codereview.chromium.org/1293373002

Cr-Commit-Position: refs/heads/master@{#344186}
void SetSecondaryDisplayLayout(DisplayLayout::Position position) {
  DisplayLayout layout =
      Shell::GetInstance()->display_manager()->GetCurrentDisplayLayout();
  layout.position = position;
  Shell::GetInstance()->display_manager()->
      SetLayoutForCurrentDisplays(layout);
}

void SetSecondaryDisplayLayout(DisplayLayout::Position position) {
  DisplayLayout layout =
      Shell::GetInstance()->display_manager()->GetCurrentDisplayLayout();
  layout.position = position;
  Shell::GetInstance()->display_manager()->
      SetLayoutForCurrentDisplays(layout);
}
