message: Eliminate the tiny gap under the embedded viewer title bar
diff: @@ -291,7 +291,7 @@ export class EmbeddedViewer extends ViewerElement implements SupportsClipboardPa
  // See VirtualScrollable
  getReserveViewportHeight(containerHeight: number): number {
  const {top, bottom} = this._borderSize();
  - const result = top + bottom;
  + const result = Math.floor(top + bottom);
  if (DEBUG_SIZE) {
  this._log.debug("getReserveViewportHeight() => ", result);
  @@ -323,7 +323,7 @@ export class EmbeddedViewer extends ViewerElement implements SupportsClipboardPa
  const headerDiv = <HTMLDivElement>this._getById(ID_HEADER);
  const headerHeightOrNull = this._getHeaderHeight();
  - const headerHeight = headerHeightOrNull == null ? 0 : Math.ceil(headerHeightOrNull);
  + const headerHeight = headerHeightOrNull == null ? 0 : Math.floor(headerHeightOrNull);
  headerDiv.style.top = Math.min(Math.max(setterState.physicalTop, 0), setterState.height - headerHeight) + 'px';
  @@ -731,8 +731,8 @@ export class EmbeddedViewer extends ViewerElement implements SupportsClipboardPa
  return { top: this._headerTop, bottom: this._headerBottom };
  }
  - const top = Math.ceil(headerHeight + DomUtils.pixelLengthToFloat(outputContainerStyle.borderTopWidth));
  - const bottom = Math.ceil(DomUtils.pixelLengthToFloat(outputContainerStyle.borderBottomWidth));
  + const top = headerHeight + DomUtils.pixelLengthToFloat(outputContainerStyle.borderTopWidth);
  + const bottom = DomUtils.pixelLengthToFloat(outputContainerStyle.borderBottomWidth);
  this._headerTop = top;
  this._headerBottom = bottom;
  