Make DataUseTabModel and DataUseMatcher more independent

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 731bf002f222766b0a609852fc232baa2a020a73..557e7f3a37fce54a090c3b59c9523f0621a9ce18 100644
--- a/chrome/browser/android/data_usage/data_use_matcher.h
+++ b/chrome/browser/android/data_usage/data_use_matcher.h
@@ -9,14 +9,13 @@
 #include <string>
 #include <vector>
 
+#include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/containers/hash_tables.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/threading/thread_checker.h"
 #include "base/time/time.h"
-#include "chrome/browser/android/data_usage/data_use_tab_model.h"
-
 namespace base {
 class TickClock;
 }
@@ -31,16 +30,22 @@ namespace chrome {
 
 namespace android {
 
-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
-// given URL or package. DataUseMatcher is not thread safe.
+// given URL or package. DataUseMatcher is not thread safe. It is created on IO
+// thread, but immediately moved to the UI thread, and afterwards accessible
+// only on the UI thread.
 class DataUseMatcher {
  public:
+  // |on_tracking_label_removed_callback| is the callback to be run when a
+  // tracking label is removed from the list of matching rules.
+  // |on_matching_rules_fetched_callback| is the callback to be run after
+  // matching rules are fetched, indicating if at least one valid matching rule
+  // is available.
   DataUseMatcher(
-      const base::WeakPtr<DataUseTabModel>& data_use_tab_model,
-      const ExternalDataUseObserverBridge* external_data_use_observer_bridge,
+      const base::Callback<void(const std::string&)>&
+          on_tracking_label_removed_callback,
+      const base::Callback<void(bool)>& on_matching_rules_fetched_callback,
       const base::TimeDelta& default_matching_rule_expiration_duration);
 
   ~DataUseMatcher();
@@ -64,10 +69,6 @@ class DataUseMatcher {
   bool MatchesAppPackageName(const std::string& app_package_name,
                              std::string* label) const WARN_UNUSED_RESULT;
 
-  // Fetches the matching rules asynchronously from
-  // |external_data_use_observer_bridge_|.
-  void FetchMatchingRules();
-
   // Returns true if there is any matching rule. HasRules may return true even
   // if all rules are expired.
   bool HasRules() const;
@@ -129,10 +130,6 @@ class DataUseMatcher {
 
   std::vector<std::unique_ptr<MatchingRule>> matching_rules_;
 
-  // |data_use_tab_model_| is notified if a label is removed from the set of
-  // matching labels.
-  base::WeakPtr<DataUseTabModel> data_use_tab_model_;
-
   // Default expiration duration of a matching rule, if expiration is not
   // specified in the rule.
   const base::TimeDelta default_matching_rule_expiration_duration_;
@@ -140,12 +137,12 @@ class DataUseMatcher {
   // TickClock used for obtaining the current time.
   std::unique_ptr<base::TickClock> tick_clock_;
 
-  // Pointer to the ExternalDataUseObserverBridge owned by
-  // ExternalDataUseObserver. DataUseTabModel (owner of |this|) and
-  // ExternalDataUseObserverBridge are owned by ExternalDataUseObserver, and are
-  // destroyed in that order. So |external_data_use_observer_bridge_| is
-  // guaranteed to be non-null.
-  const ExternalDataUseObserverBridge* external_data_use_observer_bridge_;
+  // Callback to be run when a label is removed from the set of matching labels.
+  const base::Callback<void(const std::string&)>
+      on_tracking_label_removed_callback_;
+
+  // Callback to be run when matching rules are fetched.
+  const base::Callback<void(bool)> on_matching_rules_fetched_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(DataUseMatcher);
 };