[Cronet] Enable persistence mode for Sdch

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 2f736a9dc1c3161d501ad938a1c01dbe468e7cf1..d163ff4d8d2ca5459ae200d3e68d8064ade3e908 100644
--- a/components/cronet/android/cronet_url_request_context_adapter.cc
+++ b/components/cronet/android/cronet_url_request_context_adapter.cc
@@ -11,6 +11,7 @@
 #include "base/files/scoped_file.h"
 #include "base/logging.h"
 #include "base/memory/scoped_vector.h"
+#include "base/prefs/pref_filter.h"
 #include "base/single_thread_task_runner.h"
 #include "base/values.h"
 #include "components/cronet/url_request_context_config.h"
@@ -185,6 +186,21 @@ void CronetURLRequestContextAdapter::InitializeOnNetworkThread(
   context_builder.set_net_log(net_log.release());
   context_builder.set_proxy_config_service(proxy_config_service_.release());
   config->ConfigureURLRequestContextBuilder(&context_builder);
+
+  // Set up pref file if storage path is specified.
+  if (!config->storage_path.empty()) {

[mmenke, 2015/05/26 19:34:40]

Suggest checking if sdch is enabled...Could get ugly if we start using it for my
things, but we can burn that bridge when we come to it.

[xunjieli, 2015/05/26 20:28:28]

Done. I know HttpServerProperties will use the same file. Matt, are you working
on another feature that also uses persistent pref file?

[mmenke, 2015/05/27 14:40:43]

That was a type...my == many (For some reason, a disproportionate number of my
typos end up as valid English words...Just the wrong English words).

[mmenke, 2015/05/27 14:41:31]

type == typo (Case in point...)

+    base::FilePath filepath(config->storage_path);
+    filepath = filepath.Append(FILE_PATH_LITERAL("local_prefs.json"));
+    if (!file_thread_) {

[mmenke, 2015/05/26 19:34:40]

Suggest a method GetFileThread, which creates it if needed, so we don't end up
with multiple copies of this logic.

[xunjieli, 2015/05/26 20:28:28]

Done.

+      file_thread_.reset(new base::Thread("Network File Thread"));
+      file_thread_->Start();
+    }
+    json_pref_store_ = new JsonPrefStore(filepath, file_thread_->task_runner(),
+                                         scoped_ptr<PrefFilter>());
+    json_pref_store_->ReadPrefsAsync(nullptr);
+    context_builder.SetFileTaskRunner(file_thread_->task_runner());
+  }
+
   context_.reset(context_builder.Build());
 
   default_load_flags_ = net::LOAD_DO_NOT_SAVE_COOKIES |
@@ -196,6 +212,8 @@ void CronetURLRequestContextAdapter::InitializeOnNetworkThread(
     DCHECK(context_->sdch_manager());
     sdch_owner_.reset(
         new net::SdchOwner(context_->sdch_manager(), context_.get()));
+    if (json_pref_store_)
+      sdch_owner_->EnablePersistentStorage(json_pref_store_.get());
   }
 
   // Currently (circa M39) enabling QUIC requires setting probability threshold.