message: Remove getBaseTheme
  This was only used by vector/index.js, in the code removed by
  React SDK does a very similar thing in setTheme but also gets the
  rest of the custom theme name.
  Requires
diff: @@ -127,28 +127,14 @@ function getCustomTheme(themeName) {
  return customTheme;
  }
  -/**
  - * Gets the underlying theme name for the given theme. This is usually the theme or
  - * CSS resource that the theme relies upon to load.
  - * @param {string} theme The theme name to get the base of.
  - * @returns {string} The base theme (typically "light" or "dark").
  - */
  -export function getBaseTheme(theme) {
  - if (!theme) return "light";
  - if (theme.startsWith("custom-")) {
  - const customTheme = getCustomTheme(theme.substr(7));
  - return customTheme.is_dark ? "dark-custom" : "light-custom";
  - }
  -
  - return theme; // it's probably a base theme
  -}
  -
  /**
  * Called whenever someone changes the theme
  + * Async function that returns once the theme has been set
  + * (ie. the CSS has been loaded)
  *
  * @param {string} theme new theme
  */
  -export function setTheme(theme) {
  +export async function setTheme(theme) {
  if (!theme) {
  const themeWatcher = new ThemeWatcher();
  theme = themeWatcher.getEffectiveTheme();
  @@ -190,6 +176,7 @@ export function setTheme(theme) {
  styleElements[stylesheetName].disabled = false;
  + return new Promise((resolve) => {
  const switchTheme = function() {
  // we re-enable our theme here just in case we raced with another
  // theme set request as per https://github.com/vector-im/riot-web/issues/5601.
  @@ -201,6 +188,7 @@ export function setTheme(theme) {
  a.disabled = true;
  });
  Tinter.setTheme(theme);
  + resolve();
  };
  // turns out that Firefox preloads the CSS for link elements with
  @@ -224,4 +212,5 @@ export function setTheme(theme) {
  styleElements[stylesheetName].onload = undefined;
  switchTheme();
  }
  + });
  }
  