Let MetricsService know about some Android Activities

To tune our crash states more finely, we need to track which Activity is in the
foreground when Chrome is killed. Add piping to let MetricsService know when
Activities are swapped in and out by the user.

The CL makes MetricsService track how many times particular Activities have been
launched, as well as how often Chrome was improperly closed while one of these
Activities was in the foreground (i.e. crashed). These numbers are concatenated
into a histogram, which is then sent to the server.

BUG=321346

Review URL: https://codereview.chromium.org/137623002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250410 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 7 insertions, 3 deletions

diff --git a/base/metrics/histogram_snapshot_manager.h b/base/metrics/histogram_snapshot_manager.h
index 3c70508..5a5f2e9 100644
--- a/base/metrics/histogram_snapshot_manager.h
+++ b/base/metrics/histogram_snapshot_manager.h
@@ -29,9 +29,13 @@ class BASE_EXPORT HistogramSnapshotManager {
   virtual ~HistogramSnapshotManager();
 
   // Snapshot all histograms, and ask |histogram_flattener_| to record the
-  // delta. The arguments allow selecting only a subset of histograms for
-  // recording, or to set a flag in each recorded histogram.
-  void PrepareDeltas(HistogramBase::Flags flags_to_set, bool record_only_uma);
+  // delta. |flags_to_set| is used to set flags for each histogram.
+  // |required_flags| is used to select histograms to be recorded.
+  // Only histograms that have all the flags specified by the argument will be
+  // chosen. If all histograms should be recorded, set it to
+  // |Histogram::kNoFlags|.
+  void PrepareDeltas(HistogramBase::Flags flags_to_set,
+                     HistogramBase::Flags required_flags);
 
  private:
   // Snapshot this histogram, and record the delta.