Finish NV12 support via streams.

The main functionality for NV12 texture support through EGL streams has
been added. Updates to the compiler, texture code, and stream code were
added to support binding to external D3D11 NV12 textures. An end2end test
was also added to test sampling of YUV textures and converting to RGB.
There is also a new script to convert BMP files to an NV12 texture ready
to load into D3D11 for testing purposes.

BUG=angleproject:1332

Change-Id: I39b6ec393ea338e2c843fb911acc1b36cd1158a0
Reviewed-on: https://chromium-review.googlesource.com/339454
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Ian Ewell <ewell@google.com>
Reviewed-on: https://chromium-review.googlesource.com/341254
Reviewed-by: Ian Ewell <ewell@google.com>
diff --git a/src/common/utilities.cpp b/src/common/utilities.cpp
index 2ab913b..9686c74 100644
--- a/src/common/utilities.cpp
+++ b/src/common/utilities.cpp
@@ -127,6 +127,7 @@
       case GL_SAMPLER_3D:
       case GL_SAMPLER_CUBE:
       case GL_SAMPLER_2D_ARRAY:
+      case GL_SAMPLER_EXTERNAL_OES:
       case GL_INT_SAMPLER_2D:
       case GL_INT_SAMPLER_3D:
       case GL_INT_SAMPLER_CUBE:
@@ -334,6 +335,7 @@
       case GL_SAMPLER_3D:
       case GL_SAMPLER_CUBE:
       case GL_SAMPLER_2D_ARRAY:
+      case GL_SAMPLER_EXTERNAL_OES:
       case GL_INT_SAMPLER_2D:
       case GL_INT_SAMPLER_3D:
       case GL_INT_SAMPLER_CUBE:
@@ -361,6 +363,9 @@
       case GL_SAMPLER_2D_SHADOW:
         return GL_TEXTURE_2D;
 
+      case GL_SAMPLER_EXTERNAL_OES:
+          return GL_TEXTURE_EXTERNAL_OES;
+
       case GL_SAMPLER_CUBE:
       case GL_INT_SAMPLER_CUBE:
       case GL_UNSIGNED_INT_SAMPLER_CUBE: