Revert of [ObjC ARC] Converts ios/chrome/app to ARC.

ios/chrome/app/deferred_initialization_runner.mm

Index: ios/chrome/app/deferred_initialization_runner.mm
diff --git a/ios/chrome/app/deferred_initialization_runner.mm b/ios/chrome/app/deferred_initialization_runner.mm
index 31a396807229039913f5772799e7fe1feaed9db3..7e175b4c47d604cae0d502d959e5e4f3231a851b 100644
--- a/ios/chrome/app/deferred_initialization_runner.mm
+++ b/ios/chrome/app/deferred_initialization_runner.mm
@@ -6,13 +6,10 @@
 
 #include <stdint.h>
 
+#import "base/ios/weak_nsobject.h"
 #include "base/logging.h"
 #include "base/mac/scoped_block.h"
 #include "base/mac/scoped_nsobject.h"
-
-#if !defined(__has_feature) || !__has_feature(objc_arc)
-#error "This file requires ARC support."
-#endif
 
 // An object encapsulating the deferred execution of a block of initialization
 // code.
@@ -50,7 +47,7 @@
   self = [super init];
   if (self) {
     _name.reset([name copy]);
-    _runBlock.reset(block);
+    _runBlock.reset(block, base::scoped_policy::RETAIN);
   }
   return self;
 }
@@ -105,8 +102,8 @@
 - (instancetype)init {
   self = [super init];
   if (self) {
-    _blocksNameQueue.reset([NSMutableArray array]);
-    _runBlocks.reset([NSMutableDictionary dictionary]);
+    _blocksNameQueue.reset([[NSMutableArray array] retain]);
+    _runBlocks.reset([[NSMutableDictionary dictionary] retain]);
     _isBlockScheduled = NO;
     _delayBetweenBlocks = 0.2;
     _delayBeforeFirstBlock = 3.0;
@@ -140,7 +137,8 @@
       [_runBlocks objectForKey:nextBlockName];
   DCHECK(nextBlock);
 
-  __weak DeferredInitializationRunner* weakSelf = self;
+  base::WeakNSObject<DeferredInitializationRunner> weakSelf(self);
+
   dispatch_after(
       dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delay * NSEC_PER_SEC)),
       dispatch_get_main_queue(), ^{