Implement GL_ARM_shader_framebuffer_fetch GL_ARM_shader_framebuffer_fetch allows fragment shaders to read gl_LastFragColorARM. The extension is similar to GL_EXT_shader_framebuffer_fetch, but is more limited in its capabilities. GL_ARM_shader_framebuffer_fetch was removed from HasFramebufferFetch() because it acts differently from GL_EXT_shader_framebuffer_fetch in significant enough ways that it should not be included in that single-use function. Tests: FramebufferFetchES31.*_ARM Bug: b/242419750 Bug: angleproject:7882 Change-Id: Id3a25c8ee50ca3e2a4c30a2261f507b0b53511ec Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4083108 Commit-Queue: Sean Risser <srisser@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Geoff Lang <geofflang@chromium.org>