[ObjC ARC] Converts ios/chrome/browser/ui/omnibox:omnibox_internal to ARC.

ios/chrome/browser/ui/omnibox/omnibox_popup_view_ios.h

Index: ios/chrome/browser/ui/omnibox/omnibox_popup_view_ios.h
diff --git a/ios/chrome/browser/ui/omnibox/omnibox_popup_view_ios.h b/ios/chrome/browser/ui/omnibox/omnibox_popup_view_ios.h
index f46b27945fc6329d1f443d5d55f6144a7055b14c..46c0493f82db784ff6ac9d70a70a4d30a5f42c73 100644
--- a/ios/chrome/browser/ui/omnibox/omnibox_popup_view_ios.h
+++ b/ios/chrome/browser/ui/omnibox/omnibox_popup_view_ios.h
@@ -47,8 +47,8 @@ class OmniboxPopupViewIOS : public OmniboxPopupView {
 
  private:
   std::unique_ptr<OmniboxPopupModel> model_;
-  OmniboxViewIOS* edit_view_;              // weak, owns this instance
-  id<OmniboxPopupPositioner> positioner_;  // weak
+  OmniboxViewIOS* edit_view_;  // weak, owns this instance
+  __weak id<OmniboxPopupPositioner> positioner_;

[rohitrao (ping after 24h), 2017/02/24 13:40:32]

This is ok because it happens to only be included from arc files?

We had a discussion about this last week, where I think Eric and I were in favor
of always using scoped_nsobject and __unsafe_unretained in headers, for now.

[stkhapugin, 2017/03/01 17:43:58]

This prevents this file from being included outside of ARC, but if this will be
necessary one day to include this from MRR, the compile will fail and the person
who needs the include will have to understand wether the zeroing part of the
weak reference is necessary. Since in case of omnibox it's unlikely it will be
included from MRR code after this cl lands, I think it's nice to have a zeroing
weak here. 

However if you insist, I will change to __unsafe_unretained. 

   // View that contains the omnibox popup table view and shadow.
   base::scoped_nsobject<UIView> popupView_;
   base::scoped_nsobject<OmniboxPopupMaterialViewController> popup_controller_;