This fixes a number of things that are warnings in the Mac compiler....

core/cross/display_mode.h

 /*
  * Copyright 2009, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 28 matching lines @@
 
 namespace o3d {
 
 //  A DisplayMode describes the size and refresh rate of a display mode; it's
 //  usually used in [or when transitioning into] fullscreen mode.  The id is a
 //  platform-specific opaque identifier used to identify the mode when
 //  requesting a fullscreen transition.
 class DisplayMode {
  public:
   DisplayMode()
-      : valid_(false),
-        width_(0),
+      : width_(0),
         height_(0),
         refresh_rate_(0),
-        id_(-1) {  // Since this is platform-specific, -1 may well be valid.
+        id_(-1),   // Since this is platform-specific, -1 may well be valid.
+        valid_(false) {
   }
   void Set(int w, int h, int r, int i) {
     width_ = w;
     height_ = h;
     refresh_rate_ = r;
     id_ = i;
     valid_ = true;
   }
   DisplayMode(int w, int h, int r, int i) {
     Set(w, h, r, i);
@@ skipping 40 matching lines @@
   bool valid_;
 };
 
 }  // namespace o3d
 
 #endif  // O3D_CORE_CROSS_DISPLAY_MODE_H_