Notify DataUseTabModel of navigations and tab closures

chrome/browser/io_thread.h

Index: chrome/browser/io_thread.h
diff --git a/chrome/browser/io_thread.h b/chrome/browser/io_thread.h
index f57bc395a0eb16e6b0e6966ac96c5461a152ea8d..bc8ac3c3f6f53bda27606568105d044aa667049e 100644
--- a/chrome/browser/io_thread.h
+++ b/chrome/browser/io_thread.h
@@ -39,6 +39,7 @@ class CommandLine;
 #if defined(OS_ANDROID)
 namespace chrome {
 namespace android {
+class DataUseTabModel;
 class ExternalDataUseObserver;
 }
 }
@@ -270,6 +271,9 @@ class IOThread : public content::BrowserThreadDelegate {
 chrome::android::ExternalDataUseObserver* external_data_use_observer() const {
   return external_data_use_observer_.get();
 }
+base::WeakPtr<chrome::android::DataUseTabModel> data_use_tab_model() const {
+  return data_use_tab_model_;
+}
 #endif  // defined(OS_ANDROID)
 
  private:
@@ -539,6 +543,8 @@ chrome::android::ExternalDataUseObserver* external_data_use_observer() const {
 #if defined(OS_ANDROID)
   scoped_ptr<chrome::android::ExternalDataUseObserver>
       external_data_use_observer_;
+  // WeakPtr to DataUseTabModel to be used on IO thread.
+  base::WeakPtr<chrome::android::DataUseTabModel> data_use_tab_model_;
 #endif  // defined(OS_ANDROID)
 
   const base::TimeTicks creation_time_;