Android 4.0 added ASLR
http://developer.android.com/sdk/android-4.0-highlights.html#DeveloperApis
Afaik, ASLR is mainly useful to avoid letting some malicious code leak/put a payload in another library when exploiting a buffer overflow vulnerability
But almost all of the code that'll run on android will be managed, so it shouldn't be affected by memory management errors
It can probably be useful for native code. Otoh, I thought that most of the programs that make use of the NDK (like opengl game engines made in C), still have a layer of java code to deal with the user input and such (and I think user supplied files/strings would be the main vector for malicious code)
Clearly I'm missing something in my picture