Upstream various ios/web utilities and helpers

ios/web/crw_network_activity_indicator_manager.mm

+// Copyright 2014 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/web/crw_network_activity_indicator_manager.h"
+
+#import <UIKit/UIKit.h>
+
+#include "base/logging.h"
+#include "base/mac/scoped_nsobject.h"
+#include "base/threading/thread_checker.h"
+
+@interface CRWNetworkActivityIndicatorManager () {
+  base::scoped_nsobject<NSMutableDictionary> _groupCounts;
+  NSUInteger _totalCount;
+  base::ThreadChecker _threadChecker;
+}
+
+@end
+
+@implementation CRWNetworkActivityIndicatorManager
+
++ (CRWNetworkActivityIndicatorManager*)sharedInstance {
+  static CRWNetworkActivityIndicatorManager* instance =
+      [[CRWNetworkActivityIndicatorManager alloc] init];
+  return instance;
+}
+
+- (id)init {

[Eugene But (OOO till 7-30), 2015/03/09 16:17:42]

Optional: s/id/instancetype

+  self = [super init];
+  if (self) {
+    _groupCounts.reset([[NSMutableDictionary alloc] init]);
+    _totalCount = 0;
+  }
+  return self;
+}
+
+- (void)startNetworkTaskForGroup:(NSString*)group {
+  [self startNetworkTasks:1 forGroup:group];
+}
+
+- (void)stopNetworkTaskForGroup:(NSString*)group {
+  [self stopNetworkTasks:1 forGroup:group];
+}
+
+- (void)startNetworkTasks:(NSUInteger)numTasks forGroup:(NSString*)group {
+  DCHECK(_threadChecker.CalledOnValidThread());
+  DCHECK(group);
+  DCHECK_GT(numTasks, 0U);
+  NSUInteger count = 0;
+  NSNumber* number = [_groupCounts objectForKey:group];
+  if (number) {
+    count = [number unsignedIntegerValue];
+    DCHECK_GT(count, 0U);
+  }
+  count += numTasks;
+  [_groupCounts setObject:[NSNumber numberWithUnsignedInteger:count]

[Eugene But (OOO till 7-30), 2015/03/09 16:17:42]

Optional: @(count)

+                   forKey:group];
+  _totalCount += numTasks;
+  if (_totalCount == numTasks) {
+    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
+  }
+}
+
+- (void)stopNetworkTasks:(NSUInteger)numTasks forGroup:(NSString*)group {
+  DCHECK(_threadChecker.CalledOnValidThread());
+  DCHECK(group);
+  DCHECK_GT(numTasks, 0U);
+  NSNumber* number = [_groupCounts objectForKey:group];
+  DCHECK(number);
+  NSUInteger count = [number unsignedIntegerValue];
+  DCHECK(count >= numTasks);
+  count -= numTasks;
+  if (count == 0) {
+    [_groupCounts removeObjectForKey:group];
+  } else {
+    [_groupCounts setObject:[NSNumber numberWithUnsignedInteger:count]

[Eugene But (OOO till 7-30), 2015/03/09 16:17:42]

Optional: @(count)

+                     forKey:group];
+  }
+  _totalCount -= numTasks;
+  if (_totalCount == 0) {
+    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
+  }
+}
+
+- (NSUInteger)clearNetworkTasksForGroup:(NSString*)group {
+  DCHECK(_threadChecker.CalledOnValidThread());
+  DCHECK(group);
+  NSNumber* number = [_groupCounts objectForKey:group];
+  if (!number) {
+    return 0;
+  }
+  NSUInteger count = [number unsignedIntegerValue];
+  DCHECK_GT(count, 0U);
+  [self stopNetworkTasks:count forGroup:group];
+  return count;
+}
+
+- (NSUInteger)numNetworkTasksForGroup:(NSString*)group {
+  DCHECK(_threadChecker.CalledOnValidThread());
+  DCHECK(group);
+  NSNumber* number = [_groupCounts objectForKey:group];
+  if (!number) {
+    return 0;
+  }
+  return [number unsignedIntegerValue];
+}
+
+- (NSUInteger)numTotalNetworkTasks {
+  DCHECK(_threadChecker.CalledOnValidThread());
+  return _totalCount;
+}
+

[Eugene But (OOO till 7-30), 2015/03/09 16:17:42]

Optional: extra endline

+
+@end