Remove one thread hop while fetching matching rules

chrome/browser/android/data_usage/data_use_matcher.h

Index: chrome/browser/android/data_usage/data_use_matcher.h
diff --git a/chrome/browser/android/data_usage/data_use_matcher.h b/chrome/browser/android/data_usage/data_use_matcher.h
index 9d1a12c9971404bc6ea5dd7924be12edd8a46303..21635a95fa74a491046f5bf9c62027f1c1e09d37 100644
--- a/chrome/browser/android/data_usage/data_use_matcher.h
+++ b/chrome/browser/android/data_usage/data_use_matcher.h
@@ -13,12 +13,10 @@
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/threading/thread_checker.h"

[tbansal1, 2016/03/08 18:15:00]

Why was this include removed?

[Raj, 2016/03/09 02:27:35]

Done.

 #include "base/time/time.h"
 #include "chrome/browser/android/data_usage/data_use_tab_model.h"
 
 namespace base {
-class SingleThreadTaskRunner;
 class TickClock;
 }
 
@@ -32,7 +30,7 @@ namespace chrome {
 
 namespace android {
 
-class ExternalDataUseObserver;
+class ExternalDataUseObserverBridge;
 
 // DataUseMatcher stores the matching URL patterns and package names along with
 // the labels. It also provides functionality to get the matching label for a
@@ -41,8 +39,7 @@ class DataUseMatcher {
  public:
   DataUseMatcher(
       const base::WeakPtr<DataUseTabModel>& data_use_tab_model,
-      const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner,
-      const base::WeakPtr<ExternalDataUseObserver>& external_data_use_observer,
+      const ExternalDataUseObserverBridge* external_data_use_observer_bridge,
       const base::TimeDelta& default_matching_rule_expiration_duration);
 
   ~DataUseMatcher();
@@ -67,7 +64,7 @@ class DataUseMatcher {
                              std::string* label) const WARN_UNUSED_RESULT;
 
   // Fetches the matching rules asynchronously from
-  // |external_data_use_observer_|.
+  // |external_data_use_observer_bridge_|.
   void FetchMatchingRules();
 
   // Returns true if there is any valid matching rule.
@@ -137,12 +134,12 @@ class DataUseMatcher {
 
   // TickClock used for obtaining the current time.
   scoped_ptr<base::TickClock> tick_clock_;
-  // |io_task_runner_| is used to call ExternalDataUseObserver methods on
-  // IO thread.
-  scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
 
-  // |external_data_use_observer_| is notified when matching rules are fetched.
-  base::WeakPtr<ExternalDataUseObserver> external_data_use_observer_;
+  // Pointer to the ExternalDataUseObserverBridge owned by
+  // ExternalDataUseObserver. DataUseTabModel(owner of |this|) and

[tbansal1, 2016/03/08 18:15:00]

nit: space before (

[Raj, 2016/03/09 02:27:35]

Done.

+  // ExternalDataUseObserverBridge are owned by ExternalDataUseObserver, and are
+  // destroyed in the order.
+  const ExternalDataUseObserverBridge* external_data_use_observer_bridge_;
 
   DISALLOW_COPY_AND_ASSIGN(DataUseMatcher);
 };