This CL adds some UI to remove most-visited thumbnails from the New Tab Page.

The URL of removed thumbnails is added to a blacklist, which is a user pref.

I had to modify the VisitSegmentDatabase::QuerySegmentUsage not to return a
fixed number of items, as now we may filter the ones we get back.

Note: this adds between 20 and 30ms to the first NTP load on my machine (a
3 to 5% increase).

BUG=685
TEST=Open the NTP. Click the 'Edit thumbnails' link.  Remove some thumbnails.
     Press Done. Edit again, use the "Restore removed" link.

Review URL: http://codereview.chromium.org/67037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@13611 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 17 insertions, 13 deletions

diff --git a/chrome/browser/history/history.cc b/chrome/browser/history/history.cc
index 33eb4d9..7e1130c 100644
--- a/chrome/browser/history/history.cc
+++ b/chrome/browser/history/history.cc
@@ -242,10 +242,11 @@ HistoryService::Handle HistoryService::ScheduleDBTask(
 HistoryService::Handle HistoryService::QuerySegmentUsageSince(
     CancelableRequestConsumerBase* consumer,
     const Time from_time,
+    int max_result_count,
     SegmentQueryCallback* callback) {
   return Schedule(PRIORITY_UI, &HistoryBackend::QuerySegmentUsage,
                   consumer, new history::QuerySegmentUsageRequest(callback),
-                  from_time);
+                  from_time, max_result_count);
 }
 
 void HistoryService::SetOnBackendDestroyTask(Task* task) {
diff --git a/chrome/browser/history/history.h b/chrome/browser/history/history.h
index d47f12f..eb62217 100644
--- a/chrome/browser/history/history.h
+++ b/chrome/browser/history/history.h
@@ -468,6 +468,7 @@ class HistoryService : public CancelableRequestProvider,
   // representing the segment.
   Handle QuerySegmentUsageSince(CancelableRequestConsumerBase* consumer,
                                 const base::Time from_time,
+                                int max_result_count,
                                 SegmentQueryCallback* callback);
 
   // Set the presentation index for the segment identified by |segment_id|.
diff --git a/chrome/browser/history/history_backend.cc b/chrome/browser/history/history_backend.cc
index 48a8373..d045dc9 100644
--- a/chrome/browser/history/history_backend.cc
+++ b/chrome/browser/history/history_backend.cc
@@ -846,12 +846,13 @@ void HistoryBackend::SetSegmentPresentationIndex(SegmentID segment_id,
 
 void HistoryBackend::QuerySegmentUsage(
     scoped_refptr<QuerySegmentUsageRequest> request,
-    const Time from_time) {
+    const Time from_time,
+    int max_result_count) {
   if (request->canceled())
     return;
 
   if (db_.get()) {
-    db_->QuerySegmentUsage(from_time, &request->value.get());
+    db_->QuerySegmentUsage(from_time, max_result_count, &request->value.get());
 
     // If this is the first time we query segments, invoke
     // DeleteOldSegmentData asynchronously. We do this to cleanup old
diff --git a/chrome/browser/history/history_backend.h b/chrome/browser/history/history_backend.h
index 7a66008..6201ec6 100644
--- a/chrome/browser/history/history_backend.h
+++ b/chrome/browser/history/history_backend.h
@@ -208,7 +208,8 @@ class HistoryBackend : public base::RefCountedThreadSafe<HistoryBackend>,
   // Segment usage -------------------------------------------------------------
 
   void QuerySegmentUsage(scoped_refptr<QuerySegmentUsageRequest> request,
-                         const base::Time from_time);
+                         const base::Time from_time,
+                         int max_result_count);
   void DeleteOldSegmentData();
   void SetSegmentPresentationIndex(SegmentID segment_id, int index);
 
diff --git a/chrome/browser/history/history_unittest.cc b/chrome/browser/history/history_unittest.cc
index 107d845..e64a09d 100644
--- a/chrome/browser/history/history_unittest.cc
+++ b/chrome/browser/history/history_unittest.cc
@@ -598,7 +598,7 @@ TEST_F(HistoryTest, Segments) {
 
   // Make sure a segment was created.
   history->QuerySegmentUsageSince(
-      &consumer_, Time::Now() - TimeDelta::FromDays(1),
+      &consumer_, Time::Now() - TimeDelta::FromDays(1), 10,
       NewCallback(static_cast<HistoryTest*>(this),
                   &HistoryTest::OnSegmentUsageAvailable));
 
@@ -616,7 +616,7 @@ TEST_F(HistoryTest, Segments) {
 
   // Query again
   history->QuerySegmentUsageSince(
-      &consumer_, Time::Now() - TimeDelta::FromDays(1),
+      &consumer_, Time::Now() - TimeDelta::FromDays(1), 10,
       NewCallback(static_cast<HistoryTest*>(this),
                   &HistoryTest::OnSegmentUsageAvailable));
 
@@ -633,7 +633,7 @@ TEST_F(HistoryTest, Segments) {
 
   // Query again
   history->QuerySegmentUsageSince(
-      &consumer_, Time::Now() - TimeDelta::FromDays(1),
+      &consumer_, Time::Now() - TimeDelta::FromDays(1), 10,
       NewCallback(static_cast<HistoryTest*>(this),
                   &HistoryTest::OnSegmentUsageAvailable));
 
diff --git a/chrome/browser/history/visitsegment_database.cc b/chrome/browser/history/visitsegment_database.cc
index 6bab4972..8d9c362 100644
--- a/chrome/browser/history/visitsegment_database.cc
+++ b/chrome/browser/history/visitsegment_database.cc
@@ -232,6 +232,7 @@ bool VisitSegmentDatabase::IncreaseSegmentVisitCount(SegmentID segment_id,
 
 void VisitSegmentDatabase::QuerySegmentUsage(
     const Time& from_time,
+    int max_result_count,
     std::vector<PageUsageData*>* results) {
   // This function gathers the highest-ranked segments in two queries.
   // The first gathers scores for all segments.
@@ -241,9 +242,6 @@ void VisitSegmentDatabase::QuerySegmentUsage(
   // used to lock results into position.  But the rest of our code currently
   // does as well.
 
-  // How many results we return, as promised in the header file.
-  const size_t kResultCount = 9;
-
   // Gather all the segment scores:
   SQLITE_UNIQUE_STATEMENT(statement, GetStatementCache(),
       "SELECT segment_id, time_slot, visit_count "
@@ -296,8 +294,8 @@ void VisitSegmentDatabase::QuerySegmentUsage(
 
   // Limit to the top kResultCount results.
   sort(results->begin(), results->end(), PageUsageData::Predicate);
-  if (results->size() > kResultCount)
-    results->resize(kResultCount);
+  if (static_cast<int>(results->size()) > max_result_count)
+    results->resize(max_result_count);
 
   // Now fetch the details about the entries we care about.
   SQLITE_UNIQUE_STATEMENT(statement2, GetStatementCache(),
diff --git a/chrome/browser/history/visitsegment_database.h b/chrome/browser/history/visitsegment_database.h
index 2f2bbb2..0eb0a36f 100644
--- a/chrome/browser/history/visitsegment_database.h
+++ b/chrome/browser/history/visitsegment_database.h
@@ -49,8 +49,10 @@ class VisitSegmentDatabase {
                                  int amount);
 
   // Compute the segment usage since |from_time| using the provided aggregator.
-  // A PageUsageData is added in |result| for the nine highest-scored segments.
+  // A PageUsageData is added in |result| for the highest-scored segments up to
+  // |max_result_count|.
   void QuerySegmentUsage(const base::Time& from_time,
+                         int max_result_count,
                          std::vector<PageUsageData*>* result);
 
   // Delete all the segment usage data which is older than the provided time