color: Fix color not being reset between layout tests
Layout tests run WebTestDelegate::SetDeviceColorProfile("reset") after
every test, which resets the ICC profile for rasterization to an empty
This is not the right thing to do with color correct rendering, because
it will make LayerTreeHostImpl::GetRasterColorSpace return an invalid
color space, which is used as a signal that color correct rendering is
Fix this in two ways.
First, make WebTestDelegate::SetDeviceColorProfile("reset") reset the
ICC profile to be whatever was specified at the command line.
Second, make LayerTreeHostImpl::GetRasterColorSpace never return
an invalid color space when color correct rendering is enabled.
Third, fix a bug in RenderWidget where ICCProfile::GetColorSpace is
used instead of ICCProfile::GetParametricColorSpace.