Mark RGB HALF_FLOAT_OES as renderable with EXT_color_buffer_half_float and WebGL The EXT_color_buffer_half_float spec states: If OES_texture_half_float is supported, textures created with: <internalformat> = RGBA <format> = RGBA <type> = HALF_FLOAT_OES are renderable. But WebGL content relies on being able to render to both RGB and RGBA unsized HALF_FLOAT_OES textures. Framebuffers may still return unsupported for this format. BUG=941671 Change-Id: I42d909d26508b9cdf7cda6d1dc025b0e2ed87732 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1523530 Reviewed-by: Yuly Novikov <ynovikov@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>