Notify DataUseTabModel of navigations and tab closures

chrome/browser/android/data_usage/data_use_tab_model.cc

Index: chrome/browser/android/data_usage/data_use_tab_model.cc
diff --git a/chrome/browser/android/data_usage/data_use_tab_model.cc b/chrome/browser/android/data_usage/data_use_tab_model.cc
index dea0659f0209f14ca52b02af348c47aa2ac497f3..83d09131807f526bce366c3688c0e4e4e852c066 100644
--- a/chrome/browser/android/data_usage/data_use_tab_model.cc
+++ b/chrome/browser/android/data_usage/data_use_tab_model.cc
@@ -5,10 +5,12 @@
 #include "chrome/browser/android/data_usage/data_use_tab_model.h"
 
 #include "base/metrics/histogram_macros.h"
+#include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/time/time.h"
 #include "chrome/browser/android/data_usage/external_data_use_observer.h"
 #include "chrome/browser/android/data_usage/tab_data_use_entry.h"
+#include "components/data_usage/core/data_use.h"
 #include "components/variations/variations_associated_data.h"
 
 namespace {
@@ -53,9 +55,11 @@ DataUseTabModel::DataUseTabModel(
     const ExternalDataUseObserver* data_use_observer,
     scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner)
     : data_use_observer_(data_use_observer),
-      observer_list_(new base::ObserverListThreadSafe<TabDataUseObserver>),
       max_tab_entries_(GetMaxTabEntries()),
-      weak_factory_(this) {}
+      ui_task_runner_(ui_task_runner),
+      weak_factory_(this) {
+  DCHECK(ui_task_runner_);
+}
 
 DataUseTabModel::~DataUseTabModel() {
   DCHECK(thread_checker_.CalledOnValidThread());
@@ -75,6 +79,7 @@ void DataUseTabModel::OnNavigationEvent(int32_t tab_id,
 
   switch (transition) {
     case TRANSITION_OMNIBOX_SEARCH:
+    case TRANSITION_OMNIBOX_NAVIGATION:
     case TRANSITION_FROM_EXTERNAL_APP: {
       // Enter events.
       bool start_tracking = false;
@@ -103,11 +108,8 @@ void DataUseTabModel::OnNavigationEvent(int32_t tab_id,
       break;
     }
 
-    case TRANSITION_FROM_NAVSUGGEST:
-    case TRANSITION_OMNIBOX_NAVIGATION:
     case TRANSITION_BOOKMARK:
     case TRANSITION_HISTORY_ITEM:
-    case TRANSITION_TO_EXTERNAL_APP:
       // Exit events.
       EndTrackingDataUse(tab_id);
       break;
@@ -159,12 +161,17 @@ bool DataUseTabModel::GetLabelForDataUse(const data_usage::DataUse& data_use,
   return false;  // Tab session not found.
 }
 
-void DataUseTabModel::AddObserver(TabDataUseObserver* observer) {
-  observer_list_->AddObserver(observer);
+void DataUseTabModel::AddObserver(
+    const TabDataUseObserver* observer,
+    const base::WeakPtr<TabDataUseObserver> weak_ptr_observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  observers_.insert(ObserverMap::value_type(observer, weak_ptr_observer));
+  DCHECK_LT(0U, observers_.size());
 }
 
-void DataUseTabModel::RemoveObserver(TabDataUseObserver* observer) {
-  observer_list_->RemoveObserver(observer);
+void DataUseTabModel::RemoveObserver(const TabDataUseObserver* observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  observers_.erase(observer);
 }
 
 base::TimeTicks DataUseTabModel::Now() const {
@@ -172,13 +179,23 @@ base::TimeTicks DataUseTabModel::Now() const {
 }
 
 void DataUseTabModel::NotifyObserversOfTrackingStarting(int32_t tab_id) {
-  observer_list_->Notify(FROM_HERE, &TabDataUseObserver::NotifyTrackingStarting,
-                         tab_id);
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(ui_task_runner_);
+  for (const auto& it : observers_) {
+    ui_task_runner_->PostTask(
+        FROM_HERE, base::Bind(&TabDataUseObserver::NotifyTrackingStarting,
+                              it.second, tab_id));
+  }
 }
 
 void DataUseTabModel::NotifyObserversOfTrackingEnding(int32_t tab_id) {
-  observer_list_->Notify(FROM_HERE, &TabDataUseObserver::NotifyTrackingEnding,
-                         tab_id);
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(ui_task_runner_);
+  for (const auto& it : observers_) {
+    ui_task_runner_->PostTask(
+        FROM_HERE, base::Bind(&TabDataUseObserver::NotifyTrackingEnding,
+                              it.second, tab_id));
+  }
 }
 
 void DataUseTabModel::StartTrackingDataUse(int32_t tab_id,