Turning off pixels you don't need can save substantial power consumed by an OLED display.
According to a patent the company applied for in 2009 and received confirmation on August 7, 2012, Google suggests to reduce the application UI size to enable power savings in OLED displays as fewer active pixels would consume power.
"OLED displays do not require a backlight to function and thus consume far less power than LCDs," the patent reads. "However, continual improvements in power efficiency remains desirable, especially as portable computing devices become smaller." The idea is to continuously reduce the size of the continuously UI as a user does not interact with a device. From the patent:
"For example, when the software application reduces the size of the screen 200, the screen size may be reduced from 720.times.400 to 640.times.350 after 10 seconds. After another 10 seconds, the screen size may be reduced from 640.times.350 to 320.times.200, etc. FIG. 2B illustrates an example OLED display showing the screen 200 of FIG. 2A with a reduced size. Because of the reduced screen size, fewer OLEDs are required to be on in order to generate the image of the screen 200 and its contents. As such, in one embodiment, the software application may then disable or turn off the OLEDs and/or rows of OLEDs that are not contributing to the generation of the screen 200 and its contents. This results in substantial power savings."
Given the timeframe of the invention and the patent filing, it is rather doubtful if Google has still interest in this idea.