Fix oes-texture-half-float.html on core profile GL.

ui/gl/gl_gl_api_implementation.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gl/gl_gl_api_implementation.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/stl_util.h"
@@ skipping 145 matching lines @@
         break;
       case GL_LUMINANCE_ALPHA:
         gl_internal_format = GL_LUMINANCE_ALPHA16F_ARB;
         break;
       case GL_LUMINANCE:
         gl_internal_format = GL_LUMINANCE16F_ARB;
         break;
       case GL_ALPHA:
         gl_internal_format = GL_ALPHA16F_ARB;
         break;
+      // RED and RG are reached here because on Desktop GL core profile,
+      // LUMINANCE/ALPHA formats are emulated through RED and RG in Chrome.
+      case GL_RED:
+        gl_internal_format = GL_R16F;
+        break;
+      case GL_RG:
+        gl_internal_format = GL_RG16F;
+        break;
       default:
         NOTREACHED();
         break;
     }
   }
 
   return gl_internal_format;
 }
 
 static inline GLenum GetTexFormat(GLenum format) {
@@ skipping 490 matching lines @@
 
 void VirtualGLApi::glFlushFn() {
   GLApiBase::glFlushFn();
 }
 
 void VirtualGLApi::glFinishFn() {
   GLApiBase::glFinishFn();
 }
 
 }  // namespace gl