[cronet] Expose API to set experimental options

components/cronet/ios/cronet_environment.mm

 // Copyright 2016 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 "components/cronet/ios/cronet_environment.h"
 
 #include <utility>
 
 #include "base/at_exit.h"
 #include "base/atomicops.h"
@@ skipping 248 matching lines @@
     ts->Shutdown();
 }
 
 void CronetEnvironment::InitializeOnNetworkThread() {
   DCHECK(network_io_thread_->task_runner()->BelongsToCurrentThread());
   base::FeatureList::InitializeInstance(std::string(), std::string());
 
   static bool ssl_key_log_file_set = false;
   if (!ssl_key_log_file_set && !ssl_key_log_file_name_.empty()) {
     ssl_key_log_file_set = true;
-    base::FilePath ssl_key_log_file;
-    if (!PathService::Get(base::DIR_HOME, &ssl_key_log_file))
-      return;
-    net::SSLClientSocket::SetSSLKeyLogFile(
-        ssl_key_log_file.Append(ssl_key_log_file_name_),
-        file_thread_->task_runner());
+    base::FilePath ssl_key_log_file(ssl_key_log_file_name_);
+    net::SSLClientSocket::SetSSLKeyLogFile(ssl_key_log_file,
+                                           file_thread_->task_runner());
   }
 
   if (user_agent_partial_)
     user_agent_ = web::BuildUserAgentFromProduct(user_agent_);
 
   // Cache
   base::FilePath cache_path;
   if (!PathService::Get(base::DIR_CACHE, &cache_path))
     return;
   cache_path = cache_path.Append(FILE_PATH_LITERAL("cronet"));
 
   URLRequestContextConfigBuilder context_config_builder;
   context_config_builder.enable_quic = quic_enabled_;   // Enable QUIC.
   context_config_builder.enable_spdy = http2_enabled_;  // Enable HTTP/2.
   context_config_builder.http_cache = http_cache_;      // Set HTTP cache
   context_config_builder.storage_path =
       cache_path.value();  // Storage path for http cache and cookie storage.
   context_config_builder.user_agent =
       user_agent_;  // User-Agent request header field.
+  context_config_builder.experimental_options =
+      experimental_options_;  // Set experimental Cronet options.
   context_config_builder.mock_cert_verifier = std::move(
       mock_cert_verifier_);  // MockCertVerifier to use for testing purposes.
   std::unique_ptr<URLRequestContextConfig> config =
       context_config_builder.Build();
 
   net::URLRequestContextBuilder context_builder;
 
   context_builder.set_accept_language(accept_language_);
 
   config->ConfigureURLRequestContextBuilder(&context_builder, net_log_.get(),
@@ skipping 70 matching lines @@
   event->Signal();
 }
 
 std::string CronetEnvironment::getDefaultQuicUserAgentId() const {
   return base::SysNSStringToUTF8([[NSBundle mainBundle]
              objectForInfoDictionaryKey:@"CFBundleDisplayName"]) +
          " Cronet/" + CRONET_VERSION;
 }
 
 }  // namespace cronet