src/vs/workbench/contrib/scm/browser/dirtydiffDecorator.ts/DirtyDiffModel/diff
class DirtyDiffModel:	private diff(): Promise<IChange[] | null> {
		return this.getOriginalURIPromise().then(originalURI => {
			if (this._disposed || this._model.isDisposed() || !originalURI) {
				return Promise.resolve([]); // disposed
			}

			if (!this.editorWorkerService.canComputeDirtyDiff(originalURI, this._model.resource)) {
				return Promise.resolve([]); // Files too large
			}

			return this.editorWorkerService.computeDirtyDiff(originalURI, this._model.resource, false);
		});
	}