[Cronet] Integrate CrNet functionality into Cronet on iOS.

components/cronet/ios/cronet_environment.h

Index: components/cronet/ios/cronet_environment.h
diff --git a/components/cronet/ios/cronet_environment.h b/components/cronet/ios/cronet_environment.h
index 30f29ea2c9f4ee3ebde133a822fc226e0a79a247..37459e65319ababf6f54797d0686050dc8af53de 100644
--- a/components/cronet/ios/cronet_environment.h
+++ b/components/cronet/ios/cronet_environment.h
@@ -6,6 +6,7 @@
 #define COMPONENTS_CRONET_IOS_CRONET_ENVIRONMENT_H_
 
 #include <list>
+#include <vector>
 
 #include "base/files/file_path.h"
 #include "base/macros.h"
@@ -16,6 +17,7 @@
 #include "net/cert/cert_verifier.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_context.h"
+#include "net/url_request/url_request_context_getter.h"
 
 class JsonPrefStore;
 
@@ -50,6 +52,9 @@ class CronetEnvironment {
   // The full user-agent.
   std::string user_agent();
 
+  // Get global UMA histogram deltas.
+  std::vector<uint8_t> GetHistogramDeltas();
+
   // Creates a new net log (overwrites existing file with this name). If
   // actively logging, this call is ignored.
   void StartNetLog(base::FilePath::StringType file_name, bool log_bytes);
@@ -82,6 +87,8 @@ class CronetEnvironment {
 
   net::URLRequestContext* GetURLRequestContext() const;
 
+  net::URLRequestContextGetter* GetURLRequestContextGetter() const;
+
   bool IsOnNetworkThread();
 
   // Runs a closure on the network thread.
@@ -123,6 +130,7 @@ class CronetEnvironment {
   std::unique_ptr<net::ProxyConfigService> proxy_config_service_;
   std::unique_ptr<net::HttpServerProperties> http_server_properties_;
   std::unique_ptr<net::URLRequestContext> main_context_;
+  scoped_refptr<net::URLRequestContextGetter> main_context_getter_;
   std::string user_agent_product_name_;
   std::unique_ptr<net::NetLog> net_log_;
   std::unique_ptr<net::WriteToFileNetLogObserver> net_log_observer_;