Really fix crash when dragging and dropping in chrome://settings/startup

chrome/browser/custom_home_pages_table_model.cc

Index: chrome/browser/custom_home_pages_table_model.cc
diff --git a/chrome/browser/custom_home_pages_table_model.cc b/chrome/browser/custom_home_pages_table_model.cc
index 54f1c08779141c1cd68ea67c94de41a9737c06a7..4325c4c190ee65957ee98071bcd9b908cecbabd4 100644
--- a/chrome/browser/custom_home_pages_table_model.cc
+++ b/chrome/browser/custom_home_pages_table_model.cc
@@ -96,11 +96,9 @@ void CustomHomePagesTableModel::SetURLs(const std::vector<GURL>& urls) {
  */
 void CustomHomePagesTableModel::MoveURLs(int insert_before,
                                          const std::vector<int>& index_list) {
-  // Was causing crashes when just a DCHECK(), see http://crbug.com/136576.
-  if (index_list.empty() || insert_before < 0 || insert_before > RowCount()) {
-    NOTREACHED();
-    return;
-  }
+  DCHECK(!index_list.empty());
+  DCHECK(insert_before >= 0 && insert_before <= RowCount())
+    << "Index out of range: " << insert_before;

[Dan Beam, 2013/03/09 00:22:04]

is this meant to stay here or debugging code?  I'd recommend removing the
message if it's meant to stay.  also, if insert_before == RowCount() what
happens?  I know I wrote this code but maybe I was off-by-one.

[dcheng, 2013/03/09 01:06:22]

I figured it didn't matter since it was only going to be included in debugging
builds, but removed.
We need to support this case; otherwise, we wouldn't be able to drag an item to
the end. So the code Just Works (tm) though I haven't traced through why.

 
   // The range of elements that needs to be reshuffled is [ |first|, |last| ).
   int first = std::min(insert_before, index_list.front());