Remove one thread hop while fetching matching rules

chrome/browser/android/data_usage/external_data_use_observer_bridge.cc

 // Copyright 2015 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 "chrome/browser/android/data_usage/external_data_use_observer_bridge.h"
 
 #include <vector>
 
 #include "base/android/context_utils.h"
 #include "base/android/jni_string.h"
@@ skipping 110 matching lines @@
     return;
 
   if (is_first_matching_rule_fetch_) {
     is_first_matching_rule_fetch_ = false;
     UMA_HISTOGRAM_TIMES("DataUsage.Perf.MatchingRuleFirstFetchDuration",
                         base::TimeTicks::Now() - construct_time_);
   }
 
   data_use_tab_model_->RegisterURLRegexes(
       app_package_name_native, domain_path_regex_native, label_native);
+
+  io_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&ExternalDataUseObserver::OnFetchMatchingRulesDone,

[tbansal1, 2016/03/10 01:00:58]

Why is this callback needed?  This is not preventing 2 parallel calls to the
Java class because not all FetchMatchingRules() come from EDUO.

[Raj, 2016/03/10 02:13:34]

This callback updates the last_matching_rules_fetch_time_ in EDUO, which is
relied on in test MatchingRuleFetchOnControlAppInstall to identify whether rule
fetch is invoked.
I have changed the test to look at UMA to determine rule fetch was invoked.

+                            external_data_use_observer_));
 }
 
 void ExternalDataUseObserverBridge::ReportDataUse(
     const std::string& label,
     net::NetworkChangeNotifier::ConnectionType connection_type,
     const std::string& mcc_mnc,
     const base::Time& start_time,
     const base::Time& end_time,
     int64_t bytes_downloaded,
     int64_t bytes_uploaded) const {
@@ skipping 27 matching lines @@
 }
 
 void ExternalDataUseObserverBridge::OnControlAppInstallStateChange(
     JNIEnv* env,
     jobject obj,
     bool is_control_app_installed) const {
   DCHECK(thread_checker_.CalledOnValidThread());
   data_use_tab_model_->OnControlAppInstallStateChange(is_control_app_installed);
 }
 
+void ExternalDataUseObserverBridge::ShouldRegisterAsDataUseObserver(
+    bool should_register) const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  io_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&ExternalDataUseObserver::ShouldRegisterAsDataUseObserver,
+                 external_data_use_observer_, should_register));
+}
+
 bool RegisterExternalDataUseObserver(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace android
 
 }  // namespace chrome