Fix gl::ValidTextureTarget to work on all enum values.

Change-Id: I347583ae1adcaaae9feeb1276f6150ceb8739885
Reviewed-on: https://chromium-review.googlesource.com/181557
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libGLESv2/validationES.cpp b/src/libGLESv2/validationES.cpp
index c688fcd..9f62b95 100644
--- a/src/libGLESv2/validationES.cpp
+++ b/src/libGLESv2/validationES.cpp
@@ -23,15 +23,19 @@
 
 bool ValidTextureTarget(const Context *context, GLenum target)
 {
-    if (context->getClientVersion() < 3)
+    switch (target)
     {
-        if (target == GL_TEXTURE_3D || target == GL_TEXTURE_2D_ARRAY)
-        {
-            return false;
-        }
-    }
+      case GL_TEXTURE_2D:
+      case GL_TEXTURE_CUBE_MAP:
+        return true;
 
-    return true;
+      case GL_TEXTURE_3D:
+      case GL_TEXTURE_2D_ARRAY:
+        return (context->getClientVersion() >= 3);
+
+      default:
+        return false;
+    }
 }
 
 bool ValidFramebufferTarget(GLenum target)