src/vs/editor/common/model/textModel.ts/TextModel/handleBeforeFireDecorationsChangedEvent
class TextModel:	private handleBeforeFireDecorationsChangedEvent(affectedInjectedTextLines: Set<number> | null): void {
		// This is called before the decoration changed event is fired.

		if (affectedInjectedTextLines === null || affectedInjectedTextLines.size === 0) {
			return;
		}

		const affectedLines = Array.from(affectedInjectedTextLines);
		const lineChangeEvents = affectedLines.map(lineNumber => new ModelRawLineChanged(lineNumber, this.getLineContent(lineNumber), this._getInjectedTextInLine(lineNumber)));

		this._onDidChangeInjectedText.fire(new ModelInjectedTextChangedEvent(lineChangeEvents));
	}