Remember the clear browsing data combo box selection.

chrome/browser/views/clear_browsing_data.cc

Index: chrome/browser/views/clear_browsing_data.cc
===================================================================
--- chrome/browser/views/clear_browsing_data.cc	(revision 3843)
+++ chrome/browser/views/clear_browsing_data.cc	(working copy)
@@ -98,6 +98,9 @@
 
   // Add the combo box showing how far back in time we want to delete.
   time_period_combobox_ = new views::ComboBox(this);
+  time_period_combobox_->SetSelectedItem(profile_->GetPrefs()->GetInteger(
+                                          prefs::kDeleteTimePeriod));
+  time_period_combobox_->SetListener(this);
   AddChildView(time_period_combobox_);
 }
 
@@ -302,6 +305,15 @@
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// ClearBrowsingDataView, views::ComboBoxListener implementation:
+
+void ClearBrowsingDataView::ItemChanged(views::ComboBox* sender,
+                                        int prev_index, int new_index) {
+  if (sender == time_period_combobox_ && prev_index != new_index)
+    profile_->GetPrefs()->SetInteger(prefs::kDeleteTimePeriod, new_index);
+}
+
+////////////////////////////////////////////////////////////////////////////////
 // ClearBrowsingDataView, views::ButtonListener implementation:
 
 void ClearBrowsingDataView::ButtonPressed(views::NativeButton* sender) {