Notify DataUseTabModel of navigations and tab closures

chrome/browser/android/data_usage/external_data_use_observer.h

Index: chrome/browser/android/data_usage/external_data_use_observer.h
diff --git a/chrome/browser/android/data_usage/external_data_use_observer.h b/chrome/browser/android/data_usage/external_data_use_observer.h
index 6a9c8382b88f1da13f015b503e4e8d6814a86f1f..22d459cd0a902095eebaf3d31e9eb46c47c4a494 100644
--- a/chrome/browser/android/data_usage/external_data_use_observer.h
+++ b/chrome/browser/android/data_usage/external_data_use_observer.h
@@ -112,6 +112,7 @@ class ExternalDataUseObserver : public data_usage::DataUseAggregator::Observer {
                            PeriodicFetchMatchingRules);
   FRIEND_TEST_ALL_PREFIXES(ExternalDataUseObserverTest, BufferDataUseReports);
   FRIEND_TEST_ALL_PREFIXES(ExternalDataUseObserverTest, Variations);
+  FRIEND_TEST_ALL_PREFIXES(DataUseUITabModelTest, ReportTabEventsTest);

[sclittle, 2015/11/17 22:50:12]

Why is this necessary? Can we please not make this necessary?

If many tests might want to call RegisterURLRegexes, then you could add a public
RegisterURLRegexesForTesting method, which is checked by presubmits to ensure
that it's only called by test code.

At the very least, please add a TODO for this and alphabetize this list.

[tbansal1, 2015/11/18 01:32:24]

The public function requires Java object and Java environment setup.
I thought FRIEND_TEST was slightly better because it avoid adding methods that
are called only by tests (which may increase the size of binary). I am probably
wrong?
Done.

 
   // DataUseReportKey is a unique identifier for a data use report.
   struct DataUseReportKey {