Record histogram for Clear Browsing Data deletion duration

Record how much time it takes to perform full and partial deletions.

Change-Id: I7494e96c8aaf96434389df19c85a3b40c3cdd0a4
Reviewed-on: https://chromium-review.googlesource.com/1154969Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Martin Šrámek <msramek@chromium.org>
Commit-Queue: Christian Dullweber <dullweber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580146}

content/browser/browsing_data/browsing_data_remover_impl.cc

@@ -227,7 +227,8 @@ void BrowsingDataRemoverImpl::RemoveInternal(
 
 void BrowsingDataRemoverImpl::RunNextTask() {
   DCHECK(!task_queue_.empty());
-  const RemovalTask& removal_task = task_queue_.front();
+  RemovalTask& removal_task = task_queue_.front();
+  removal_task.task_started = base::Time::Now();
 
   RemoveImpl(removal_task.delete_begin, removal_task.delete_end,
              removal_task.remove_mask, *removal_task.filter_builder,
@@ -550,9 +551,22 @@ void BrowsingDataRemoverImpl::Notify() {
   // itself in the meantime.
   DCHECK(!task_queue_.empty());
 
-  if (task_queue_.front().observer != nullptr &&
-      observer_list_.HasObserver(task_queue_.front().observer)) {
-    task_queue_.front().observer->OnBrowsingDataRemoverDone();
+  const RemovalTask& task = task_queue_.front();
+  if (task.observer != nullptr && observer_list_.HasObserver(task.observer)) {
+    task.observer->OnBrowsingDataRemoverDone();
+  }
+  if (task.filter_builder->GetMode() == BrowsingDataFilterBuilder::BLACKLIST) {
+    base::TimeDelta delta = base::Time::Now() - task.task_started;
+    // Full and partial deletions are often implemented differently, so
+    // we track them in seperate metrics.
+    if (task.delete_begin.is_null() && task.delete_end.is_max() &&
+        task.filter_builder->IsEmptyBlacklist()) {
+      UMA_HISTOGRAM_MEDIUM_TIMES(
+          "History.ClearBrowsingData.Duration.FullDeletion", delta);
+    } else {
+      UMA_HISTOGRAM_MEDIUM_TIMES(
+          "History.ClearBrowsingData.Duration.PartialDeletion", delta);
+    }
   }
 
   task_queue_.pop();

content/browser/browsing_data/browsing_data_remover_impl.h

@@ -116,6 +116,7 @@ class CONTENT_EXPORT BrowsingDataRemoverImpl
     int origin_type_mask;
     std::unique_ptr<BrowsingDataFilterBuilder> filter_builder;
     Observer* observer;
+    base::Time task_started;
   };
 
   // Setter for |is_removing_|; DCHECKs that we can only start removing if we're

tools/metrics/histograms/histograms.xml

@@ -33969,6 +33969,24 @@ uploading your change for review.
   </summary>
 </histogram>
 
+<histogram name="History.ClearBrowsingData.Duration.FullDeletion" units="ms">
+  <owner>dullweber@chromium.org</owner>
+  <owner>msramek@chromium.org</owner>
+  <summary>
+    The time that passed while performing a full browsing data deletion.
+  </summary>
+</histogram>
+
+<histogram name="History.ClearBrowsingData.Duration.PartialDeletion" units="ms">
+  <owner>dullweber@chromium.org</owner>
+  <owner>msramek@chromium.org</owner>
+  <summary>
+    The time that passed while performing a browsing data deletion for a
+    restricted amount of time (e.g. &quot;Last hour&quot;) or with an origin
+    filter.
+  </summary>
+</histogram>
+
 <histogram
     name="History.ClearBrowsingData.HistoryNoticeShownInFooterWhenUpdated"
     enum="BooleanShown">