Add stubs for EGL image entry points and validation.

BUG=angleproject:970

Change-Id: Ic3b9f9f60146920571e0e5f00fac2273c35fff2f
Reviewed-on: https://chromium-review.googlesource.com/287162
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/validationES.cpp b/src/libANGLE/validationES.cpp
index 7f28528..9213e81 100644
--- a/src/libANGLE/validationES.cpp
+++ b/src/libANGLE/validationES.cpp
@@ -2001,4 +2001,21 @@
     return true;
 }
 
+bool ValidateEGLImageTargetTexture2DOES(Context *context,
+                                        egl::Display *display,
+                                        GLenum target,
+                                        egl::Image *image)
+{
+    UNIMPLEMENTED();
+    return true;
+}
+
+bool ValidateEGLImageTargetRenderbufferStorageOES(Context *context,
+                                                  egl::Display *display,
+                                                  GLenum target,
+                                                  egl::Image *image)
+{
+    UNIMPLEMENTED();
+    return true;
+}
 }