Add GLSL/ESSL validator/translator support for GL_EXT_shader_framebuffer_fetch.

BUG=angle:834

Change-Id: I2d4e25909a8e1266b9bb7f1d4421324143157c8a
Reviewed-on: https://chromium-review.googlesource.com/231032
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Erik Dahlström <ed@opera.com>
diff --git a/src/compiler/translator/ShaderLang.cpp b/src/compiler/translator/ShaderLang.cpp
index ebbd68a..03a9aef 100644
--- a/src/compiler/translator/ShaderLang.cpp
+++ b/src/compiler/translator/ShaderLang.cpp
@@ -154,6 +154,9 @@
     resources->EXT_frag_depth = 0;
     resources->EXT_shader_texture_lod = 0;
     resources->WEBGL_debug_shader_precision = 0;
+    resources->EXT_shader_framebuffer_fetch = 0;
+    resources->NV_shader_framebuffer_fetch = 0;
+    resources->ARM_shader_framebuffer_fetch = 0;
 
     resources->NV_draw_buffers = 0;