Support usampler throughout the compiler.

TRAC #23360
Signed-off-by: Jamie Madill
Signed-off-by: Shannon Woods
Author: Nicolas Capens
diff --git a/src/compiler/VariableInfo.cpp b/src/compiler/VariableInfo.cpp
index e6163bd..a8dd472 100644
--- a/src/compiler/VariableInfo.cpp
+++ b/src/compiler/VariableInfo.cpp
@@ -101,6 +101,8 @@
       case EbtSampler2DRect: return SH_SAMPLER_2D_RECT_ARB;
       case EbtISampler2D: return SH_INT_SAMPLER_2D;
       case EbtISamplerCube: return SH_INT_SAMPLER_CUBE;
+      case EbtUSampler2D: return SH_UNSIGNED_INT_SAMPLER_2D;
+      case EbtUSamplerCube: return SH_UNSIGNED_INT_SAMPLER_CUBE;
       default: UNREACHABLE();
     }
     return SH_NONE;