Validate level exists for TexSubImage calls.

Before validating the texture format, verify that the texture level already
exists in glTexSubImage calls.

BUG=602737

Change-Id: I0d83c7d43c7b358abdb59583dc83265df70c13b5
Reviewed-on: https://chromium-review.googlesource.com/411361
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/tests/gl_tests/TextureTest.cpp b/src/tests/gl_tests/TextureTest.cpp
index d917343..ee2fc7c 100644
--- a/src/tests/gl_tests/TextureTest.cpp
+++ b/src/tests/gl_tests/TextureTest.cpp
@@ -1194,6 +1194,16 @@
     const GLubyte *pixels[20] = { 0 };
     glTexSubImage2D(GL_TEXTURE_2D, 0, 1, 1, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
     EXPECT_GL_ERROR(GL_INVALID_VALUE);
+
+    if (extensionEnabled("GL_EXT_texture_storage"))
+    {
+        // Create a 1-level immutable texture.
+        glTexStorage2DEXT(GL_TEXTURE_2D, 1, GL_RGBA8, 2, 2);
+
+        // Try calling sub image on the second level.
+        glTexSubImage2D(GL_TEXTURE_2D, 1, 1, 1, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+        EXPECT_GL_ERROR(GL_INVALID_OPERATION);
+    }
 }
 
 // Test that querying GL_TEXTURE_BINDING* doesn't cause an unexpected error.