Advertise robustness extension strings.

Trac #18607
Signed-off-by: Daniel Koch
Author: Nicolas Capens

git-svn-id: https://angleproject.googlecode.com/svn/trunk@850 736b8ea6-26fd-11df-bfd4-992fa37f6226
diff --git a/src/libEGL/Display.cpp b/src/libEGL/Display.cpp
index 360c695..38221e1 100644
--- a/src/libEGL/Display.cpp
+++ b/src/libEGL/Display.cpp
@@ -1017,6 +1017,10 @@
 
     mExtensionString = "";
 
+    // Multi-vendor (EXT) extensions
+    mExtensionString += "EGL_EXT_create_context_robustness ";
+
+    // ANGLE-specific extensions
     if (isd3d9ex) {
         mExtensionString += "EGL_ANGLE_d3d_share_handle_client_buffer ";
     }