Build Cronet for iOS with ARC enabled

BUG=774225

Cq-Include-Trybots: master.tryserver.chromium.android:android_cronet_tester;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I7ca92a5f81520bcd7f7736a43181de79031fb9e5
Reviewed-on: https://chromium-review.googlesource.com/716777
Reviewed-by: Misha Efimov <mef@chromium.org>
Commit-Queue: Andrei Kapishnikov <kapishnikov@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#508731}(cherry picked from commit bd67093)
Reviewed-on: https://chromium-review.googlesource.com/721459
Cr-Commit-Position: refs/branch-heads/3239@{#10}
Cr-Branched-From: adb61db-refs/heads/master@{#508578}

components/cronet/ios/BUILD.gn

@@ -94,6 +94,8 @@ source_set("cronet_sources") {
   if (!use_platform_icu_alternatives) {
     deps += [ "//base:i18n" ]
   }
+
+  configs += [ "//build/config/compiler:enable_arc" ]
 }
 
 source_set("cronet_sources_with_global_state") {
@@ -186,6 +188,7 @@ static_library("cronet_static") {
   public_deps = [
     "//components/grpc_support",
   ]
+  configs += [ "//build/config/compiler:enable_arc" ]
 }
 
 # A static library which contains all dependencies of :cronet_static.

components/cronet/ios/Cronet.mm

@@ -23,6 +23,10 @@
 #include "net/cert/cert_verifier.h"
 #include "net/url_request/url_request_context_getter.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 // Cronet NSError constants.
 NSString* const CRNCronetErrorDomain = @"CRNCronetErrorDomain";
 NSString* const CRNInvalidArgumentKey = @"CRNInvalidArgumentKey";
@@ -82,11 +86,11 @@ int Verify(const RequestParams& params,
  public:
   CronetHttpProtocolHandlerDelegate(net::URLRequestContextGetter* getter,
                                     RequestFilterBlock filter)
-      : getter_(getter), filter_(filter, base::scoped_policy::RETAIN) {}
+      : getter_(getter), filter_(filter) {}
 
   void SetRequestFilterBlock(RequestFilterBlock filter) {
     base::AutoLock auto_lock(lock_);
-    filter_.reset(filter, base::scoped_policy::RETAIN);
+    filter_.reset(filter);
   }
 
  private:

components/cronet/ios/cronet_environment.mm

@@ -56,6 +56,10 @@
 #include "url/scheme_host_port.h"
 #include "url/url_util.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 
 // Request context getter for Cronet.

components/cronet/tools/generate_accept_languages.py

@@ -31,7 +31,7 @@ def gen_accept_langs_table():
   return dict(accept_langs for accept_langs in accept_langs_list
     if accept_langs)
 
-HEADER = "NSDictionary* acceptLangs = @{"
+HEADER = "static NSDictionary* const acceptLangs = @{"
 def LINE(locale, accept_langs):
   return '  @"' + locale + '" : @"' + accept_langs + '",'
 FOOTER = "};"