fix #821: auto-click OneDrive popup login button if it's the only option

app/scripts/storage/storage-base.js

@@ -146,9 +146,11 @@ _.extend(StorageBase.prototype, {
             .replace('{scope}', encodeURIComponent(opts.scope))
             .replace('{url}', encodeURIComponent(this._getOauthRedirectUrl()));
         this.logger.debug('OAuth: popup opened');
-        if (!this._openPopup(url, 'OAuth', opts.width, opts.height)) {
+        const popupWindow = this._openPopup(url, 'OAuth', opts.width, opts.height);
+        if (!popupWindow) {
             return callback('OAuth: cannot open popup');
         }
+        this._popupOpened(popupWindow);
         const popupClosed = () => {
             Backbone.off('popup-closed', popupClosed);
             window.removeEventListener('message', windowMessage);
@@ -177,6 +179,9 @@ _.extend(StorageBase.prototype, {
         window.addEventListener('message', windowMessage);
     },
 
+    _popupOpened(popupWindow) {
+    },
+
     _oauthProcessReturn: function(message) {
         const token = this._oauthMsgToToken(message);
         if (token && !token.error) {

app/scripts/storage/storage-onedrive.js

@@ -239,6 +239,22 @@ const StorageOneDrive = StorageBase.extend({
             width: 600,
             height: 500
         };
+    },
+
+    _popupOpened(popupWindow) {
+        if (popupWindow.webContents) {
+            popupWindow.webContents.on('did-finish-load', (e) => {
+                const webContents = e.sender.webContents;
+                const url = webContents.getURL();
+                if (url && url.startsWith('https://login.microsoftonline.com/common/oauth2/v2.0/authorize')) {
+                    // click the login button mentioned in #821
+                    const script =
+`const selector = '[role="button"][aria-describedby="tileError loginHeader"]';
+if (document.querySelectorAll(selector).length === 1) document.querySelector(selector).click()`;
+                    webContents.executeJavaScript(script);
+                }
+            });
+        }
     }
 });