Merge from master

src/vs/code/electron-main/theme.ts

@@ -0,0 +1,39 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { isWindows, isMacintosh } from 'vs/base/common/platform';
+import { systemPreferences } from 'electron';
+import { IStateService } from 'vs/platform/state/common/state';
+
+export const DEFAULT_BG_LIGHT = '#FFFFFF';
+export const DEFAULT_BG_DARK = '#1E1E1E';
+export const DEFAULT_BG_HC_BLACK = '#000000';
+
+export const THEME_STORAGE_KEY = 'theme';
+export const THEME_BG_STORAGE_KEY = 'themeBackground';
+
+export function getBackgroundColor(stateService: IStateService): string {
+	if (isWindows && systemPreferences.isInvertedColorScheme()) {
+		return DEFAULT_BG_HC_BLACK;
+	}
+
+	let background = stateService.getItem<string | null>(THEME_BG_STORAGE_KEY, null);
+	if (!background) {
+		let baseTheme: string;
+		if (isWindows && systemPreferences.isInvertedColorScheme()) {
+			baseTheme = 'hc-black';
+		} else {
+			baseTheme = stateService.getItem<string>(THEME_STORAGE_KEY, 'vs-dark').split(' ')[0];
+		}
+
+		background = (baseTheme === 'hc-black') ? DEFAULT_BG_HC_BLACK : (baseTheme === 'vs' ? DEFAULT_BG_LIGHT : DEFAULT_BG_DARK);
+	}
+
+	if (isMacintosh && background.toUpperCase() === DEFAULT_BG_DARK) {
+		background = '#171717'; // https://github.com/electron/electron/issues/5150
+	}
+
+	return background;
+}