Which one mobile phones are super powerful?
I just made what you said "one solid color square having a sine behavior with empty background" and added extra sprite font to display some info
Tested on two devices I had in front of me: 3 years old Samsung Galaxy S3 (Android 4.3) and Sony Xperia something (Android 4.1). Both are not new and not powerful at all, just plain mobile phones from previous era xD
Build in XDK 1995 with CW12
On both devices: webgl is on, cpu usage 4-5%, fps 60. all works fine, nice and smooth.
Here are capx and apk files