[ObjC ARC] Converts ios/chrome/browser/ui/history:unit_tests to ARC.

ios/chrome/browser/ui/history/favicon_view_provider_unittest.mm

Index: ios/chrome/browser/ui/history/favicon_view_provider_unittest.mm
diff --git a/ios/chrome/browser/ui/history/favicon_view_provider_unittest.mm b/ios/chrome/browser/ui/history/favicon_view_provider_unittest.mm
index 6ec3886f61082cd040f568489f8973c2a732f5f3..009e6785a070bc3b25b8f0cc8b79e924453c70fa 100644
--- a/ios/chrome/browser/ui/history/favicon_view_provider_unittest.mm
+++ b/ios/chrome/browser/ui/history/favicon_view_provider_unittest.mm
@@ -9,7 +9,6 @@
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
-#include "base/mac/scoped_nsobject.h"
 #include "base/path_service.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/sys_string_conversions.h"
@@ -30,6 +29,10 @@
 #include "third_party/skia/include/core/SkColor.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 @interface FaviconViewProvider (Testing)
 @property(nonatomic, retain) UIImage* favicon;
 @property(nonatomic, copy) NSString* fallbackText;
@@ -98,14 +101,14 @@ class FaviconViewProviderTest : public PlatformTest {
 TEST_F(FaviconViewProviderTest, Favicon) {
   id mock_delegate =
       [OCMockObject mockForProtocol:@protocol(FaviconViewProviderDelegate)];
-  base::scoped_nsobject<FaviconViewProvider> viewProvider(
+  FaviconViewProvider* viewProvider =
       [[FaviconViewProvider alloc] initWithURL:GURL(kTestFaviconURL)
                                    faviconSize:kTestFaviconSize
                                 minFaviconSize:kTestFaviconSize
                               largeIconService:large_icon_service_.get()
-                                      delegate:mock_delegate]);
+                                      delegate:mock_delegate];
   void (^confirmationBlock)(NSInvocation*) = ^(NSInvocation* invocation) {
-    FaviconViewProvider* viewProvider;
+    __unsafe_unretained FaviconViewProvider* viewProvider;
     [invocation getArgument:&viewProvider atIndex:2];
     EXPECT_NSNE(nil, viewProvider.favicon);
   };
@@ -123,16 +126,16 @@ TEST_F(FaviconViewProviderTest, FallbackIcon) {
 
   id mock_delegate =
       [OCMockObject mockForProtocol:@protocol(FaviconViewProviderDelegate)];
-  base::scoped_nsobject<FaviconViewProvider> item([[FaviconViewProvider alloc]
-           initWithURL:GURL(kTestFallbackURL)
-           faviconSize:kTestFaviconSize
-        minFaviconSize:kTestFaviconSize
-      largeIconService:large_icon_service_.get()
-              delegate:mock_delegate]);
+  FaviconViewProvider* item =
+      [[FaviconViewProvider alloc] initWithURL:GURL(kTestFallbackURL)
+                                   faviconSize:kTestFaviconSize
+                                minFaviconSize:kTestFaviconSize
+                              largeIconService:large_icon_service_.get()
+                                      delegate:mock_delegate];
 
   // Confirm that fallback text and color have been set before delegate call.
   void (^confirmationBlock)(NSInvocation*) = ^(NSInvocation* invocation) {
-    FaviconViewProvider* viewProvider;
+    __unsafe_unretained FaviconViewProvider* viewProvider;
     [invocation getArgument:&viewProvider atIndex:2];
     // Fallback text is the first letter of the URL.
     NSString* defaultText = @"T";