Add angle_gl_library_type to allow making static libGLESv2 and libEGL With this commit angle programs can be run under apitrace: when we use shared libraries, the apitrace driver shim shadows ANGLE and redirects the GL calls to the driver, which is not what we want. BUG=angleproject:892 Change-Id: I32535ba8db6202b0b5b285e86abd472366ee3d03 Reviewed-on: https://chromium-review.googlesource.com/287270 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Corentin Wallez <cwallez@chromium.org>