You should specify which version of Ubuntu you are using (Desktop [LXDE, XFCE, KDE, Mate, Unity], which processor type [32-bit, ia64, 64-bit and so on] and which edition you are using [12.04, 14.04, 16.04 or other]) to enable the answers you are presented to be more accurately directed at your needs.
If you have ubuntu restricted extras installed you should also have ffmpeg [and here is where the edition of Ubuntu is important because gstreamer0.10-ffmpeg does not exist for 16.04] installed as well as libavcodec54 libav-tools, ffmpeg, gstreamer0.10-ffmpeg, libavcodec-extra-53, libavcodec-extra-54 and/or others to ensure you have full coverage for (nearly) all audio and video file types you should follow and install the list of codecs and apps presented by Arch Linux (I am only linking to Arch Linux because I have not been able to discover a Ubuntu page which covers as much and Arch Linux covers things exceptionally well on the following page) - https://wiki.archlinux.org/index.php/codecs
But, if you are only concerned with AAC and have already installed Ubuntu-Restricted-Extras (as you stated you had) then I strongly suggest installing Clementine which does play AAC so long as the codec is installed (and for you it is because you made clear that you have already installed Ubuntu restricted extras). So,
sudo apt-get install clementine and you will be able to play AAC files using that application.
Apart from installing clementine if you must use VLC then you need to install a few more packages.
sudo apt-get install libavcodec-extra libavcodec-ffmpeg-extra56 libavcodec-ffmpeg56 libavutil-ffmpeg54
Once installed, open VLC and in the settings make the following changes:
Open VLC. Click "Tools" then click "Preferences" In preferences select "All" in Show Settings at the bottom of the window. Find "Input / Codecs" then "Video Codecs". Now click "FFmpeg" and scroll down (on the right) until you see "Strict Standard Compliance" and change it to -2, then "Specify AAC Audio Profile" to use hev2 (just type it in after removing what was there). Save it and your VLC will play AAC files.
As for webm files I do not have as much nor am able to find one so I cannot provide a useful answer (except to say that VideoLaAN, the company which makes VLC states that webm files are covered after VLC version 1.1.0, but that was released years ago). I will continue to look for a webm file and try to provide you a manner to enable as much in your VLC.