if one plays a full screen video on android (i'm using Nexus 5), and attaches the device inspector while it's playing, playback will hang after a variable number of seconds.

this behavior shows up in 248b114c9d3034964c7259222712dfcccfad8f48 (Get rid of gpu related switches by passing gpu::GpuPreferences via IPC, penghuang@).  it is not present in the CL immediately before it.

i'm splitting this away from 592798.