UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.162 Safari/537.36

Steps to reproduce the problem:
Issue detected through Electron 1.7.8 (and most likely all other versions):

Electron calls this API here: https://github.com/electron/electron/blob/8c2c7c3634b2af71c1aaa9544114ee835fbdbb5e/lib/browser/chrome-extension.js#L287

If one decides to mimic this behaviour to load other extensions, 2 calls to DevToolsAPI.addExtensions can be issued at the same time.

What is the expected behavior?
The 2 calls to DevToolsAPI.addExtensions should install all given extensions.

What went wrong?
Only last call to DevToolsAPI.addExtensions is taken into account.

Here:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/devtools/front_end/extensions/ExtensionServer.js?type=cs&q=addExtensions&sq=package:chromium&l=676

_pendingExtensionInfos is overwritten at each addExtensions until ExtensionServer is initialized.

Did this work before? No 

Chrome version: 58.0.3029.110  Channel: stable
OS Version: OS X 10.13.3
Flash Version: