Make GL_OES_rgb8_rgba8 enableable.

Allow unsized RGB/UNSIGNED_BYTE without the rgb8rgba8 extension.

BUG=angleproject:1523

Change-Id: Ic7b4236c7b8389952b093719f26840ea2bbd01bf
Reviewed-on: https://chromium-review.googlesource.com/742501
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/libANGLE/formatutils.cpp b/src/libANGLE/formatutils.cpp
index cf4a2fb..047c547 100644
--- a/src/libANGLE/formatutils.cpp
+++ b/src/libANGLE/formatutils.cpp
@@ -845,7 +845,7 @@
     AddRGBAFormat(&map, GL_RED,              false,  8,  0,  0,  0, 0, GL_RED,          GL_BYTE,                         GL_SIGNED_NORMALIZED,   false, NeverSupported,                               NeverSupported,                               NeverSupported );
     AddRGBAFormat(&map, GL_RG,               false,  8,  8,  0,  0, 0, GL_RG,           GL_UNSIGNED_BYTE,                GL_UNSIGNED_NORMALIZED, false, RequireExt<&Extensions::textureRG>,           AlwaysSupported,                              AlwaysSupported);
     AddRGBAFormat(&map, GL_RG,               false,  8,  8,  0,  0, 0, GL_RG,           GL_BYTE,                         GL_SIGNED_NORMALIZED,   false, NeverSupported,                               NeverSupported,                               NeverSupported );
-    AddRGBAFormat(&map, GL_RGB,              false,  8,  8,  8,  0, 0, GL_RGB,          GL_UNSIGNED_BYTE,                GL_UNSIGNED_NORMALIZED, false, RequireESOrExt<3, 0, &Extensions::rgb8rgba8>, RequireESOrExt<3, 0, &Extensions::rgb8rgba8>, AlwaysSupported);
+    AddRGBAFormat(&map, GL_RGB,              false,  8,  8,  8,  0, 0, GL_RGB,          GL_UNSIGNED_BYTE,                GL_UNSIGNED_NORMALIZED, false, RequireES<2, 0>,                              AlwaysSupported,                              AlwaysSupported);
     AddRGBAFormat(&map, GL_RGB,              false,  5,  6,  5,  0, 0, GL_RGB,          GL_UNSIGNED_SHORT_5_6_5,         GL_UNSIGNED_NORMALIZED, false, RequireES<2, 0>,                              RequireES<2, 0>,                              AlwaysSupported);
     AddRGBAFormat(&map, GL_RGB,              false,  8,  8,  8,  0, 0, GL_RGB,          GL_BYTE,                         GL_SIGNED_NORMALIZED,   false, NeverSupported,                               NeverSupported,                               NeverSupported );
     AddRGBAFormat(&map, GL_RGBA,             false,  4,  4,  4,  4, 0, GL_RGBA,         GL_UNSIGNED_SHORT_4_4_4_4,       GL_UNSIGNED_NORMALIZED, false, RequireES<2, 0>,                              RequireES<2, 0>,                              AlwaysSupported);