CrNet: add pauseable NSURLProtocol and switch to using it

ios/crnet/crnet_consumer/main.m

 // 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 <Foundation/Foundation.h>
-#import <UIKit/UIKit.h>
+
+#import "CrNet.h"
 
 #import "crnet_consumer_app_delegate.h"
 
+@interface TestDelegate : NSObject <NSURLSessionDelegate,
+                                    NSURLSessionDataDelegate,
+                                    NSURLSessionTaskDelegate>
+
+- (id)initWithSemaphore:(dispatch_semaphore_t)sem;
+
+@end
+
+@implementation TestDelegate {
+  dispatch_semaphore_t _sem;
+}
+
+- (id)initWithSemaphore:(dispatch_semaphore_t)sem {
+  _sem = sem;
+  return self;
+}
+
+- (void)URLSession:(NSURLSession *)session
+didBecomeInvalidWithError:(NSError *)error {
+  NSLog(@"URLSession didBecomeInvalidWithError %@", error);
+}
+
+- (void)URLSession:(NSURLSession *)session
+              task:(NSURLSessionTask *)task
+didCompleteWithError:(NSError *)error {
+  NSLog(@"URLSessionTask didCompleteWithError %@", error);
+  dispatch_semaphore_signal(_sem);
+}
+
+- (void)URLSession:(NSURLSession *)session
+              task:(NSURLSessionTask *)task
+didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge
+ completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disp,
+                             NSURLCredential* credential))completionHandler {
+  NSLog(@"URLSessionTask didReceiveChallenge %@", challenge);
+  completionHandler(NSURLSessionAuthChallengeUseCredential, nil);
+}
+
+- (void)URLSession:(NSURLSession *)session
+              task:(NSURLSessionTask *)task
+willPerformHTTPRedirection:(NSHTTPURLResponse *)response
+        newRequest:(NSURLRequest *)request
+completionHandler:(void (^)(NSURLRequest *))completionHandler {
+  NSLog(@"URLSessionTask willPerformHttpRedirection %@", request);
+  completionHandler(request);
+}
+
+- (void)URLSession:(NSURLSession *)session
+          dataTask:(NSURLSessionDataTask *)dataTask
+didReceiveResponse:(NSURLResponse *)response
+ completionHandler:(void (^)(NSURLSessionResponseDisposition
+    disposition))completionHandler {
+  NSHTTPURLResponse* resp = (NSHTTPURLResponse *)response;
+  NSLog(@"URLSessionDataTask didReceiveResponse status %ld",
+        (long)resp.statusCode);
+  completionHandler(NSURLSessionResponseAllow);
+}
+
+- (void)URLSession:(NSURLSession *)session
+          dataTask:(NSURLSessionDataTask *)dataTask
+    didReceiveData:(NSData *)data {
+  NSLog(@"URLSessionDataTask didReceiveData %lu bytes",
+        (unsigned long)data.length);
+}
+
+- (void)URLSession:(NSURLSession *)session
+          dataTask:(NSURLSessionDataTask *)dataTask
+ willCacheResponse:(NSCachedURLResponse *)proposedResponse
+ completionHandler:(void (^)(NSCachedURLResponse
+    *cachedResponse))completionHandler {
+  NSLog(@"URLSessionDataTask willCacheResponse %@", proposedResponse);
+  completionHandler(proposedResponse);
+}
+
+@end
+
+void use_crnet(NSURLSessionConfiguration* config) {
+  [CrNet setPartialUserAgent:@"Foo/1.0"];
+  [CrNet install];
+  [CrNet installIntoSessionConfiguration:config];
+}
+
+void fetch(NSURLSession* session, NSString* url) {
+  NSURL* testURL = [NSURL URLWithString:url];
+  NSURLSessionDataTask* task = [session dataTaskWithURL:testURL];
+  NSLog(@"fetch: starting %@", url);
+  [task resume];
+}
+
 int main(int argc, char *argv[]) {
-  @autoreleasepool {
-    return UIApplicationMain(
-        argc, argv, nil, NSStringFromClass([CrNetConsumerAppDelegate class]));
-  }
+  dispatch_semaphore_t sem = dispatch_semaphore_create(0);
+  TestDelegate* delegate = [[TestDelegate alloc] initWithSemaphore:sem];
+  NSURLSessionConfiguration* config =
+      [NSURLSessionConfiguration ephemeralSessionConfiguration];
+  NSURLSession* session =
+      [NSURLSession sessionWithConfiguration:config
+                                    delegate:delegate
+                               delegateQueue:nil];
+
+  NSLog(@"main: installing crnet");
+  use_crnet(config);
+
+  fetch(session, @"https://www.google.com");
+  fetch(session, @"https://twitter.com");
+  fetch(session, @"https://m.facebook.com");
+  fetch(session, @"https://www.yahoo.com");
+
+  int64_t secs = 1000000000LL;
+  secs *= 5LL;
+  NSLog(@"main: waiting");
+  dispatch_semaphore_wait(sem, dispatch_time(DISPATCH_TIME_NOW, secs));
+  dispatch_semaphore_wait(sem, dispatch_time(DISPATCH_TIME_NOW, secs));
+  dispatch_semaphore_wait(sem, dispatch_time(DISPATCH_TIME_NOW, secs));
+  dispatch_semaphore_wait(sem, dispatch_time(DISPATCH_TIME_NOW, secs));
+  NSLog(@"main: timeout, exiting");
 }