Fix incorrect use of AXState caused when refactoring two enums into one.

ui/accessibility/ax_view_state.h

Index: ui/accessibility/ax_view_state.h
diff --git a/ui/accessibility/ax_view_state.h b/ui/accessibility/ax_view_state.h
index 2cb2152db930002fc6f6f6729d941c8da537ac0c..4c6e77fd3774aa396c71f8ffe0609aa7149751e2 100644
--- a/ui/accessibility/ax_view_state.h
+++ b/ui/accessibility/ax_view_state.h
@@ -26,6 +26,10 @@ struct AX_EXPORT AXViewState {
   AXViewState();
   ~AXViewState();
 
+  // Convenience functions to set or check bits in |state|.
+  void SetStateFlag(ui::AXState state);

[mpichlinski, 2014/03/18 08:32:34]

This only adds flags, its for previous usage of |= operator, so it should be
AddStateFlag. In some places flags are overridden to one value by = operator, so
there should be another method SetStateFlag, which will do { state = (1 <<
flag); }.

[dmazzoni, 2014/03/22 14:28:01]

In typical programming and computer science jargon, when you have a bitmask
containing flags, you "set" a flag, or "set" a bit - you don't add it.

There should never be a place in the code where the whole flag bitmask is
overridden. The way AXViewState is used is that when the native views
accessibility system needs accessibility information about a view, it calls
View::GetAccessibleState and passes it an empty AXViewState. Each view
implements it and occasionally sets flags. Often a view class will call its
inherited
GetAccessibleState or delegate, but currently we don't ever need to clear/unset
a bit.

I didn't see any code that set "state" to a value because it wanted to
explicitly clear other flags, I just saw it where it set it to a particular
value because it assumed it was previously 0 so there'd be no difference.

[mpichlinski, 2014/03/24 08:43:41]

Done.

+  bool HasStateFlag(ui::AXState state) const;
+
   // The view's role, like button or list box.
   AXRole role;