src/vs/editor/browser/viewParts/minimap/minimap.ts/MinimapSamplingState/onLinesDeleted
class MinimapSamplingState:	public onLinesDeleted(e: viewEvents.ViewLinesDeletedEvent): [number, number] {
		// have the mapping be sticky
		const deletedLineCount = e.toLineNumber - e.fromLineNumber + 1;
		let changeStartIndex = this.minimapLines.length;
		let changeEndIndex = 0;
		for (let i = this.minimapLines.length - 1; i >= 0; i--) {
			if (this.minimapLines[i] < e.fromLineNumber) {
				break;
			}
			if (this.minimapLines[i] <= e.toLineNumber) {
				// this line got deleted => move to previous available
				this.minimapLines[i] = Math.max(1, e.fromLineNumber - 1);
				changeStartIndex = Math.min(changeStartIndex, i);
				changeEndIndex = Math.max(changeEndIndex, i);
			} else {
				this.minimapLines[i] -= deletedLineCount;
			}
		}
		return [changeStartIndex, changeEndIndex];
	}