Add Data Saver support to Cronet

components/cronet/android/cronet_url_request_context_adapter.cc

Index: components/cronet/android/cronet_url_request_context_adapter.cc
diff --git a/components/cronet/android/cronet_url_request_context_adapter.cc b/components/cronet/android/cronet_url_request_context_adapter.cc
index 5a1f56921a8d34720f8aea0ad9a9780ff18cc234..1f2b29f9497506f20b8f6c2b0f591948ae1b91df 100644
--- a/components/cronet/android/cronet_url_request_context_adapter.cc
+++ b/components/cronet/android/cronet_url_request_context_adapter.cc
@@ -10,8 +10,10 @@
 #include "base/files/file_util.h"
 #include "base/files/scoped_file.h"
 #include "base/logging.h"
+#include "base/memory/scoped_vector.h"
 #include "base/single_thread_task_runner.h"
 #include "base/values.h"
+#include "components/cronet/android/cronet_data_reduction_proxy.h"
 #include "components/cronet/url_request_context_config.h"
 #include "jni/CronetUrlRequestContext_jni.h"
 #include "net/base/load_flags.h"
@@ -22,6 +24,7 @@
 #include "net/proxy/proxy_service.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_context_builder.h"
+#include "net/url_request/url_request_interceptor.h"
 
 namespace {
 
@@ -150,10 +153,32 @@ void CronetURLRequestContextAdapter::InitializeOnNetworkThread(
   DCHECK(proxy_config_service_);
   // TODO(mmenke):  Add method to have the builder enable SPDY.
   net::URLRequestContextBuilder context_builder;
-  context_builder.set_network_delegate(new BasicNetworkDelegate());
+  scoped_ptr<net::NetLog> net_log(new net::NetLog);
+  DCHECK(!data_reduction_proxy_);
+  // For now, the choice to enable the data reduction proxy happens once,
+  // at initialization. It cannot be disabled thereafter.
+  if (config->enable_data_reduction_proxy) {

[mmenke, 2015/04/24 19:10:28]

Wasn't there a decision to make it so Cronet could be build without the DRP, out
of concerns about binary size (Not that I expect there to be a huge difference).

[bengr, 2015/04/24 21:13:51]

Yes. I'm going to write that CL write after this one.

+    data_reduction_proxy_.reset(
+        new CronetDataReductionProxy(
+            config->data_reduction_proxy_key,
+            config->data_reduction_primary_proxy,
+            config->data_reduction_fallback_proxy,
+            config->data_reduction_secure_proxy_check_url,
+            config->user_agent,
+            GetNetworkTaskRunner(),
+            net_log.get()));
+    context_builder.set_network_delegate(
+        data_reduction_proxy_->CreateNetworkDelegate(
+            make_scoped_ptr(new BasicNetworkDelegate())).release());
+    ScopedVector<net::URLRequestInterceptor> interceptors;
+    interceptors.push_back(data_reduction_proxy_->CreateInterceptor());
+    context_builder.SetInterceptors(interceptors.Pass());
+  } else {
+    context_builder.set_network_delegate(new BasicNetworkDelegate());
+  }

[mmenke, 2015/04/24 19:27:23]

optional:  Think this may be a little cleaner as:

scoped_ptr<NetworkDelegate> network_delegate(new BasicNetworkDelegate());
if (config->enable_data_reduction_proxy) {
  ...
  network_delegate =
      data_reduction_proxy_->CreateNetworkDelegate(network_delegate.release());
  ...
}

context_builder.set_network_delegate(network_delegate.release());

[bengr, 2015/04/24 21:13:51]

Done.

+  context_builder.set_net_log(net_log.release());
   context_builder.set_proxy_config_service(proxy_config_service_.release());
   config->ConfigureURLRequestContextBuilder(&context_builder);
-
   context_.reset(context_builder.Build());
 
   default_load_flags_ = net::LOAD_DO_NOT_SAVE_COOKIES |
@@ -214,6 +239,10 @@ void CronetURLRequestContextAdapter::InitializeOnNetworkThread(
     tasks_waiting_for_context_.front().Run();
     tasks_waiting_for_context_.pop();
   }
+  if (data_reduction_proxy_) {

[mmenke, 2015/04/24 19:27:23]

This should probably go just before the "is_context_initialized_ = true;", since
it's really a part of context init.

[bengr, 2015/04/24 21:13:50]

Done.

+    data_reduction_proxy_->Init(config->enable_data_reduction_proxy,
+                                GetURLRequestContext());
+  }
 }
 
 void CronetURLRequestContextAdapter::Destroy(JNIEnv* env, jobject jcaller) {