Revert 95611 - Always call the class methods to save/restore contexts.

ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h

Index: ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h
===================================================================
--- ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h	(revision 95630)
+++ ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h	(working copy)
@@ -4,27 +4,23 @@
 
 #ifndef UI_GFX_SCOPED_NS_GRAPHICS_CONTEXT_SAVE_GSTATE_MAC_H_
 #define UI_GFX_SCOPED_NS_GRAPHICS_CONTEXT_SAVE_GSTATE_MAC_H_
-#pragma once
 
-#include "base/basictypes.h"
 #include "ui/ui_api.h"
+#include "base/basictypes.h"
+#include "base/memory/scoped_nsobject.h"
 
-#if defined(__OBJC__)
 @class NSGraphicsContext;
-#else
-class NSGraphicsContext;
-#endif
 
 namespace gfx {
 
-// A class to save/restore the state of the current context.
 class UI_API ScopedNSGraphicsContextSaveGState {
  public:
-  ScopedNSGraphicsContextSaveGState();
+  // If |context| is nil, it will use the |+currentContext|.
+  explicit ScopedNSGraphicsContextSaveGState(NSGraphicsContext* context = nil);
   ~ScopedNSGraphicsContextSaveGState();
 
  private:
-  NSGraphicsContext* context_;  // weak
+  scoped_nsobject<NSGraphicsContext> context_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedNSGraphicsContextSaveGState);
 };