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

ios/chrome/app/deferred_initialization_runner.mm

 // Copyright 2012 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/app/deferred_initialization_runner.h"
 
 #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.
 @interface DeferredInitializationBlock : NSObject {
   // A string to reference the initialization block.
   base::scoped_nsobject<NSString> _name;
   // A block of code to execute.
   base::mac::ScopedBlock<ProceduralBlock> _runBlock;
 }
 
 - (instancetype)init NS_UNAVAILABLE;
@@ skipping 16 matching lines @@
 - (instancetype)init {
   NOTREACHED();
   return nil;
 }
 
 - (instancetype)initWithName:(NSString*)name block:(ProceduralBlock)block {
   DCHECK(block);
   self = [super init];
   if (self) {
     _name.reset([name copy]);
-    _runBlock.reset(block);
+    _runBlock.reset(block, base::scoped_policy::RETAIN);
   }
   return self;
 }
 
 - (void)run {
   DCHECK([NSThread isMainThread]);
   ProceduralBlock deferredBlock = _runBlock.get();
   if (!deferredBlock)
     return;
   deferredBlock();
@@ skipping 34 matching lines @@
   static DeferredInitializationRunner* instance = nil;
   dispatch_once(&once, ^{
     instance = [[DeferredInitializationRunner alloc] init];
   });
   return instance;
 }
 
 - (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;
   }
   return self;
 }
 
 - (void)enqueueBlockNamed:(NSString*)name block:(ProceduralBlock)block {
   DCHECK(name);
   DCHECK([NSThread isMainThread]);
@@ skipping 13 matching lines @@
   DCHECK([NSThread isMainThread]);
   _isBlockScheduled = NO;
   NSString* nextBlockName = [_blocksNameQueue firstObject];
   if (!nextBlockName)
     return;
 
   DeferredInitializationBlock* nextBlock =
       [_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(), ^{
         [nextBlock run];
         [weakSelf scheduleNextBlockWithDelay:[weakSelf delayBetweenBlocks]];
       });
 
   _isBlockScheduled = YES;
   [_blocksNameQueue removeObjectAtIndex:0];
 }
 
 - (void)runBlockIfNecessary:(NSString*)name {
   DCHECK([NSThread isMainThread]);
   [[_runBlocks objectForKey:name] run];
 }
 
 - (void)cancelBlockNamed:(NSString*)name {
   DCHECK([NSThread isMainThread]);
   DCHECK(name);
   [_blocksNameQueue removeObject:name];
   [[_runBlocks objectForKey:name] cancel];
   [_runBlocks removeObjectForKey:name];
 }
 
 - (NSUInteger)numberOfBlocksRemaining {
   return [_runBlocks count];
 }
 
 @end