Omnibox - Fix Rare HQP Crash

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 239 matching lines @@
   match.contents = net::FormatUrlWithAdjustments(
       info.url(), languages_, format_types, net::UnescapeRule::SPACES, NULL,
       NULL, &adjustments);
   base::OffsetAdjuster::AdjustOffsets(adjustments, &offsets);
   TermMatches new_matches =
       ReplaceOffsetsInTermMatches(history_match.url_matches, offsets);
   match.contents_class =
       SpansFromTermMatch(new_matches, match.contents.length(), true);
 
   // 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@) do not
+  // know under what circumstances this can occur.
+  // See crbug.com/464926.
   if (history_match.can_inline) {
-    DCHECK(!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);
+    DCHECK(!new_matches.empty()) << "url=" << info.url().spec() << " input="
+        << autocomplete_input_.text() << " history_match.url_matches.size="
+        << history_match.url_matches.size() << " offsets.size="
+        << offsets.size();
+    if (!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);
+      }
+      match.allowed_to_be_default_match = match.inline_autocompletion.empty() ||
+          !PreventInlineAutocomplete(autocomplete_input_);
     }
-    match.allowed_to_be_default_match = match.inline_autocompletion.empty() ||
-        !PreventInlineAutocomplete(autocomplete_input_);
   }
   match.EnsureUWYTIsAllowedToBeDefault(
       autocomplete_input_.canonicalized_url(),
       TemplateURLServiceFactory::GetForProfile(profile_));
 
   // Format the description autocomplete presentation.
   match.description = info.title();
   match.description_class = SpansFromTermMatch(
       history_match.title_matches, match.description.length(), false);
 
   match.RecordAdditionalInfo("typed count", info.typed_count());
   match.RecordAdditionalInfo("visit count", info.visit_count());
   match.RecordAdditionalInfo("last visit", info.last_visit());
 
   return match;
 }