First version of the time slicing on the urls. Not ready for review yet.

chrome/browser/history/visitsegment_database.h

Index: chrome/browser/history/visitsegment_database.h
diff --git a/chrome/browser/history/visitsegment_database.h b/chrome/browser/history/visitsegment_database.h
index 4afa25998226b47c1ead23fa4f66f7cda06ff56c..95eed5718b4e978ed638e1e9f8a71c33b5b220d4 100644
--- a/chrome/browser/history/visitsegment_database.h
+++ b/chrome/browser/history/visitsegment_database.h
@@ -58,6 +58,14 @@ class VisitSegmentDatabase {
                          int max_result_count,
                          std::vector<PageUsageData*>* result);
 
+  // Compute the segment usage from |from_time| to |to_time| using the provided
+  // aggregator. A PageUsageData is added in |result| for the highest-scored
+  // segments up to |max_result_count|.
+  void QuerySegmentUsageTimeInterval(base::Time from_time,
+                                     base::Time to_time,
+                                     int max_result_count,
+                                     std::vector<PageUsageData*>* result);
+
   // Delete all the segment usage data which is older than the provided time
   // stamp.
   bool DeleteSegmentData(base::Time older_than);