Use wide gamut only when necessary

Set the dataspace of the screenshot based on the result of
the composition. When no wide gamut app is visible, the screenshot
will be in sRGB, otherwise in Display P3. On device that do not
support wide gamut, the color space will be unknown (native).

Bug: 29940137
Test: screencap and Android Studio
Change-Id: I93f3f8e5afebb9f3f17b835fdf5bc215b0856d55