gpu: Clarify sized texture format is available only if ES3 context or immutable texture is supported

gpu/command_buffer/tests/gl_texture_storage_unittest.cc

 // Copyright 2014 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 <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 #include <stdint.h>
 
 #include "gpu/command_buffer/tests/gl_manager.h"
 #include "gpu/command_buffer/tests/gl_test_utils.h"
@@ skipping 138 matching lines @@
                0,
                GL_RGBA,
                4, 4,
                0,
                GL_RGBA,
                GL_UNSIGNED_BYTE,
                NULL);
   EXPECT_EQ(static_cast<GLenum>(GL_INVALID_OPERATION), glGetError());
 }
 
+TEST_F(TextureStorageTest, InternalFormatBleedingToTexImage) {
+  if (!extension_available_)
+    return;
+
+  EXPECT_EQ(static_cast<GLenum>(GL_NO_ERROR), glGetError());
+  // The context is ES2 context.
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8_OES, 4, 4, 0, GL_RGBA,
+               GL_UNSIGNED_BYTE, nullptr);
+  EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), glGetError());
+}
+
 }  // namespace gpu