fix --show-composited-layer-borders on Mac

gpu/command_buffer/build_gles2_cmd_buffer.py

Index: gpu/command_buffer/build_gles2_cmd_buffer.py
diff --git a/gpu/command_buffer/build_gles2_cmd_buffer.py b/gpu/command_buffer/build_gles2_cmd_buffer.py
index 49518430b545ed91b835d9c2168106ed3692ba2b..eb1f2a0fb00d649862c718433b09e159268f61bb 100755
--- a/gpu/command_buffer/build_gles2_cmd_buffer.py
+++ b/gpu/command_buffer/build_gles2_cmd_buffer.py
@@ -501,7 +501,8 @@ _STATES = {
   # GL_ACTIVE_TEXTURE
   'LineWidth': {
     'type': 'Normal',
-    'func': 'LineWidth',
+    'custom_function' : True,
+    'func': 'DoLineWidth',
     'enum': 'GL_LINE_WIDTH',
     'states': [
       {
@@ -10273,7 +10274,10 @@ void ContextState::InitState(const ContextState *prev_state) const {
                            (item_name, item_name))
             if test_prev:
               f.write("    )\n")
-            f.write("  gl%s(%s);\n" % (state['func'], ", ".join(args)))
+            if 'custom_function' in state:
+              f.write("  %s(%s);\n" % (state['func'], ", ".join(args)))
+            else:
+              f.write("  gl%s(%s);\n" % (state['func'], ", ".join(args)))
 
       f.write("  if (prev_state) {")
       WriteStates(True)