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

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ios/chrome/browser/ui/history/favicon_view_provider.h"
 
 #include <memory>
 
 #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"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/favicon/core/favicon_client.h"
 #include "components/favicon/core/favicon_service.h"
 #include "components/favicon/core/large_icon_service.h"
 #include "components/favicon_base/fallback_icon_style.h"
 #include "components/favicon_base/favicon_types.h"
 #include "ios/chrome/browser/chrome_paths.h"
 #include "ios/web/public/test/test_web_thread.h"
 #include "ios/web/public/test/test_web_thread_bundle.h"
 #include "skia/ext/skia_utils_ios.h"
 #include "testing/gtest_mac.h"
 #include "testing/platform_test.h"
 #include "third_party/ocmock/OCMock/OCMock.h"
 #include "third_party/ocmock/gtest_support.h"
 #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;
 @property(nonatomic, retain) UIColor* fallbackBackgroundColor;
 @property(nonatomic, retain) UIColor* fallbackTextColor;
 @end
 
 namespace {
 
 // Dummy URL for the favicon case.
@@ skipping 81 matching lines @@
   web::TestWebThreadBundle thread_bundle_;
   std::unique_ptr<MockFaviconService> mock_favicon_service_;
   std::unique_ptr<TestLargeIconService> large_icon_service_;
   base::CancelableTaskTracker cancelable_task_tracker_;
 };
 
 // Tests that image is set when a favicon is returned from LargeIconService.
 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;

[noyau (Ping after 24h), 2017/01/27 16:04:38]

Needs a comment.

[stkhapugin, 2017/02/02 15:29:23]

Don't think this needs a comment:
This is the only way one can use [NSInvocation getArgument:atIndex:] with ARC.
Expect to see a lot of this in unit tests. 

     [invocation getArgument:&viewProvider atIndex:2];
     EXPECT_NSNE(nil, viewProvider.favicon);
   };
   [[[mock_delegate stub] andDo:confirmationBlock]
       faviconViewProviderFaviconDidLoad:viewProvider];
   EXPECT_OCMOCK_VERIFY(mock_delegate);
 }
 
 // Tests that fallback data is set when no favicon is returned from
 // LargeIconService.
 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;

[sczs, 2017/01/27 18:55:40]

There's probably a good reason, just want to know why use __unsafe_unretained
instead of __weak, if this is ARC __weak should be supported right?

[stkhapugin, 2017/02/02 15:29:23]

Unfortunately in this case only __unsafe_uretained can be used, because ARC
cannot infer any memory semantics when you do NSInvocation getArgument:atIndex:.
This is okay because when an invocation exists, you expect its arguments to be
properly memory managed, and you are usually not going to affect object
lifetimes anyway, just like here. 

     [invocation getArgument:&viewProvider atIndex:2];
     // Fallback text is the first letter of the URL.
     NSString* defaultText = @"T";
     // Default colors are defined in
     // components/favicon_base/fallback_icon_style.h.
     UIColor* defaultTextColor = skia::UIColorFromSkColor(SK_ColorWHITE);
     UIColor* defaultBackgroundColor =
         skia::UIColorFromSkColor(SkColorSetRGB(0x78, 0x78, 0x78));
     EXPECT_NSEQ(defaultText, viewProvider.fallbackText);
     EXPECT_NSEQ(defaultTextColor, viewProvider.fallbackTextColor);
     EXPECT_NSEQ(defaultBackgroundColor, viewProvider.fallbackBackgroundColor);
   };
   [[[mock_delegate stub] andDo:confirmationBlock]
       faviconViewProviderFaviconDidLoad:item];
   EXPECT_OCMOCK_VERIFY(mock_delegate);
 }
 
 }  // namespace