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
diff --git a/ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h b/ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h
index 05bf5f660f38e9a58ba5d3b324a52e4db437a13e..e86a767cb75a33155d0bc407119ddd6c6addd25f 100644
--- a/ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h
+++ b/ui/gfx/scoped_ns_graphics_context_save_gstate_mac.h
@@ -7,21 +7,17 @@
 

[Mark Mentovai, 2011/08/04 23:20:17]

Add #pragma once.

[Avi (use Gerrit), 2011/08/05 00:18:50]

Done.

 #include "ui/ui_api.h"

[Mark Mentovai, 2011/08/04 23:20:17]

Sort headers: base < ui.

[Avi (use Gerrit), 2011/08/05 00:18:50]

Done.

 #include "base/basictypes.h"
-#include "base/memory/scoped_nsobject.h"
 
 @class NSGraphicsContext;

[Mark Mentovai, 2011/08/04 23:20:17]

I would do:

#if defined(__OBJC__)
@class NSGraphicsContext;
#else
class NSGraphicsContext;
#endif

because there’s nothing inherently Objective about this interface. I doubt
anyone would want to use it from non-Objective-C code, but hey, it’s possible.

[Avi (use Gerrit), 2011/08/05 00:18:50]

Removed; not needed.

 
 namespace gfx {
 
+// A class to save/restore the state of the current context.
 class UI_API ScopedNSGraphicsContextSaveGState {
  public:
-  // If |context| is nil, it will use the |+currentContext|.
-  explicit ScopedNSGraphicsContextSaveGState(NSGraphicsContext* context = nil);
+  ScopedNSGraphicsContextSaveGState();
   ~ScopedNSGraphicsContextSaveGState();
 
- private:
-  scoped_nsobject<NSGraphicsContext> context_;

[Robert Sesek, 2011/08/04 22:15:44]

So if we were to be paranoid, we'd keep a weak ptr here and DCHECK_EQ in the
dtor that +currentContext == the pointer. Paranoia is maybe a good thing (tm)?

[Avi (use Gerrit), 2011/08/04 22:21:03]

You mean before the save context and after the restore? Not sure if it's
paranoia or not trusting the OS to do its job...

[Robert Sesek, 2011/08/04 22:22:13]

No, it'd prevent changing the current context within the scope of the scoper.

-
   DISALLOW_COPY_AND_ASSIGN(ScopedNSGraphicsContextSaveGState);

[Mark Mentovai, 2011/08/04 23:20:17]

This needs to be in a private: section.

[Avi (use Gerrit), 2011/08/05 00:18:50]

Done.

 };