frameworks/base/opengl: Add NULL check

Check for the validity of the attrs_list in eglChooseConfig before using
it. This avoids a crash during tests in which the attributes are NULL.

Change-Id: I1c0a46b505ae919e2454cfdce32f8dfc21ead247
diff --git a/opengl/libs/EGL/egl.cpp b/opengl/libs/EGL/egl.cpp
index 40317e7..de740a3 100644
--- a/opengl/libs/EGL/egl.cpp
+++ b/opengl/libs/EGL/egl.cpp
@@ -843,10 +843,13 @@
     EGLint patch_index = -1;
     GLint attr;
     size_t size = 0;
-    while ((attr=attrib_list[size]) != EGL_NONE) {
-        if (attr == EGL_CONFIG_ID)
-            patch_index = size;
-        size += 2;
+
+    if (attrib_list != NULL) {
+        while ((attr=attrib_list[size]) != EGL_NONE) {
+            if (attr == EGL_CONFIG_ID)
+                patch_index = size;
+            size += 2;
+        }
     }
     if (patch_index >= 0) {
         size += 2; // we need copy the sentinel as well