Omnibox: Fix HQP Crash on Bad FormatURL and can_inline Interaction

chrome/browser/autocomplete/history_quick_provider.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/autocomplete/history_quick_provider.h"
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
@@ skipping 244 matching lines @@
       AutocompleteInput::FormattedStringWithEquivalentMeaning(info.url(),
           net::FormatUrlWithOffsets(info.url(), languages_, format_types,
               net::UnescapeRule::SPACES, NULL, NULL, &offsets));
   history::TermMatches new_matches =
       ReplaceOffsetsInTermMatches(history_match.url_matches(), offsets);
   match.contents = net::FormatUrl(info.url(), languages_, format_types,
               net::UnescapeRule::SPACES, NULL, NULL, NULL);
   match.contents_class =
       SpansFromTermMatch(new_matches, match.contents.length(), true);
 
-  if (history_match.can_inline()) {
-    DCHECK(!new_matches.empty());
+  // Set |inline_autocompletion| and |allowed_to_be_default_match| if possible.
+  // The second part of this test can happen if the only match(es) of the user's
+  // term occur in places FormatUrl() decides to omit in the formatted url.
+  // In these cases, it's impossible to set |inline_autocompletion| correctly
+  // and hence the match cannot be the default match.  I (mpearson@) believe
+  // this is likely caused by the mismatch that offsets are originally
+  // computed with respect to the cleaned-up URL yet then applied and
+  // updated by FormatUrl() as if they applied to the original string.
+  // See crbug.com/252630.
+  // TODO(mpearson): replacing the second clause with a DCHECK after fixing
+  // 252630.
+  if (history_match.can_inline() && !new_matches.empty()) {
     size_t inline_autocomplete_offset = new_matches[0].offset +
         new_matches[0].length;
     // |inline_autocomplete_offset| may be beyond the end of the
     // |fill_into_edit| if the user has typed an URL with a scheme and the
     // last character typed is a slash.  That slash is removed by the
     // FormatURLWithOffsets call above.
     if (inline_autocomplete_offset < match.fill_into_edit.length()) {
       match.inline_autocompletion =
           match.fill_into_edit.substr(inline_autocomplete_offset);
     }
@@ skipping 17 matching lines @@
   if (index_for_testing_.get())
     return index_for_testing_.get();
 
   HistoryService* const history_service =
       HistoryServiceFactory::GetForProfile(profile_, Profile::EXPLICIT_ACCESS);
   if (!history_service)
     return NULL;
 
   return history_service->InMemoryIndex();
 }