[ios] Adds a buildflag for the ios_app_bundle_id_prefix.

ios/chrome/common/app_group/app_group_constants.mm

 // Copyright 2015 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.
 
 #include "ios/chrome/common/app_group/app_group_constants.h"
 
 #include "base/logging.h"
 #include "base/strings/sys_string_conversions.h"
+#include "build/config/ios/ios_app_bundle_id_prefix.h"
 #include "components/version_info/version_info.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
-namespace {
-NSString* const kChromeAppGroupIdentifier =
-    @"group." IOS_BUNDLE_ID_PREFIX ".chrome";
-}
-
 namespace app_group {
 
 const char kChromeAppGroupXCallbackCommand[] = "app-group-command";
 
 const char kChromeAppGroupCommandPreference[] =
     "GroupApp.ChromeAppGroupCommand";
 
 const char kChromeAppGroupCommandTimePreference[] = "CommandTime";
 
 const char kChromeAppGroupCommandAppPreference[] = "SourceApp";
@@ skipping 14 matching lines @@
 NSString* const kShareItemURL = @"URL";
 NSString* const kShareItemTitle = @"Title";
 NSString* const kShareItemDate = @"Date";
 NSString* const kShareItemCancel = @"Cancel";
 NSString* const kShareItemType = @"Type";
 
 NSString* ApplicationGroup() {
   NSBundle* bundle = [NSBundle mainBundle];
   NSString* group = [bundle objectForInfoDictionaryKey:@"KSApplicationGroup"];
   if (![group length]) {
-    return kChromeAppGroupIdentifier;
+    return [NSString stringWithFormat:@"group.%s.chrome",
+                                      BUILDFLAG(IOS_APP_BUNDLE_ID_PREFIX), nil];

[rohitrao (ping after 24h), 2016/12/13 14:14:30]

Is there a better way to concatenate these strings?

[sdefresne, 2016/12/13 15:18:02]

Ah, BUILDFLAG(IOS_APP_BUNDLE_ID_PREFIX) expands to ("org.chromium") and we
cannot use the concatenation from the preprocessor. That's lame.

I don't think there is a better way that stringWithFormat here. Should only
happens for non official builds though (since official sets KSApplicationGroup
IIRC).

   }
   return group;
 }
 
 NSString* ApplicationName(AppGroupApplications application) {
   switch (application) {
     case APP_GROUP_CHROME:
       return base::SysUTF8ToNSString(version_info::GetProductName());
     case APP_GROUP_TODAY_EXTENSION:
       return @"TodayExtension";
@@ skipping 18 matching lines @@
 NSURL* ShareExtensionItemsFolder() {
   NSURL* groupURL = [[NSFileManager defaultManager]
       containerURLForSecurityApplicationGroupIdentifier:ApplicationGroup()];
   NSURL* readingListURL =
       [groupURL URLByAppendingPathComponent:@"ShareExtensionItems"
                                 isDirectory:YES];
   return readingListURL;
 }
 
 }  // namespace app_group