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

ios/chrome/browser/ui/omnibox/truncating_attributed_label.mm

Index: ios/chrome/browser/ui/omnibox/truncating_attributed_label.mm
diff --git a/ios/chrome/browser/ui/omnibox/truncating_attributed_label.mm b/ios/chrome/browser/ui/omnibox/truncating_attributed_label.mm
index 0474a6143ce81462df6930875db980bfa9091af2..213a0f61b57c584144340b3813b20d4003125cbf 100644
--- a/ios/chrome/browser/ui/omnibox/truncating_attributed_label.mm
+++ b/ios/chrome/browser/ui/omnibox/truncating_attributed_label.mm
@@ -6,9 +6,12 @@
 
 #include <algorithm>
 
-#include "base/mac/objc_property_releaser.h"
 #include "base/mac/scoped_cftyperef.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 @interface OmniboxPopupTruncatingLabel ()
 - (void)setup;
 - (UIImage*)getLinearGradient:(CGRect)rect;
@@ -16,9 +19,7 @@
 
 @implementation OmniboxPopupTruncatingLabel {
   // Gradient used to create fade effect. Changes based on view.frame size.
-  base::scoped_nsobject<UIImage> gradient_;
-
-  base::mac::ObjCPropertyReleaser propertyReleaser_OmniboxPopupTruncatingLabel_;
+  UIImage* gradient_;
 }
 
 @synthesize truncateMode = truncateMode_;
@@ -31,8 +32,6 @@
 - (id)initWithFrame:(CGRect)frame {
   self = [super initWithFrame:frame];
   if (self) {
-    propertyReleaser_OmniboxPopupTruncatingLabel_.Init(
-        self, [OmniboxPopupTruncatingLabel class]);
     self.lineBreakMode = NSLineBreakByClipping;
     [self setup];
   }
@@ -49,9 +48,9 @@
 
   // Cache the fade gradient when the frame changes.
   if (!CGRectIsEmpty(frame) &&
-      (!gradient_.get() || !CGSizeEqualToSize([gradient_ size], frame.size))) {
+      (!gradient_ || !CGSizeEqualToSize([gradient_ size], frame.size))) {
     CGRect rect = CGRectMake(0, 0, frame.size.width, frame.size.height);
-    gradient_.reset([[self getLinearGradient:rect] retain]);
+    gradient_ = [self getLinearGradient:rect];
   }
 }
 
@@ -66,9 +65,9 @@
   // Add the specified line break and alignment attributes to attributedText and
   // draw the result.
   NSMutableAttributedString* attributedString =
-      [[self.attributedText mutableCopy] autorelease];
+      [self.attributedText mutableCopy];
   NSMutableParagraphStyle* textStyle =
-      [[[NSParagraphStyle defaultParagraphStyle] mutableCopy] autorelease];
+      [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
   textStyle.lineBreakMode = self.lineBreakMode;
   textStyle.alignment = self.textAlignment;
   [attributedString addAttribute:NSParagraphStyleAttributeName
@@ -91,7 +90,7 @@
   }
 
   if (textAlignment != self.textAlignment)
-    gradient_.reset();
+    gradient_ = nil;
 
   [super setTextAlignment:textAlignment];
 }