Move context state related methods out of DecoderContext

This CL adds a new GLContextVirtualDelegate interface to contain all
context state related methods from DecoderContext. After this one, I am
going to implement GLContextVirtualDelegate in RasterDecoderContextState
and only create one GLContextVirtual for all raster decoder and display

Bug: 900941, 902904
Change-Id: I10d80bea8531885c449a2e676ce0552e9363b34c
Reviewed-by: Antoine Labour <>
Commit-Queue: Peng Huang <>
Cr-Commit-Position: refs/heads/master@{#606777}
11 files changed