Make sure we can still navigate to URLs when the History DB can't be loaded.

BUG=25822
TEST=Make your History files non-readable, run Chrome (Release), Type in "test.com" and see that the selected action is navigation.
Review URL: http://codereview.chromium.org/343051

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@30633 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 19 insertions, 4 deletions

diff --git a/chrome/browser/autocomplete/history_url_provider.cc b/chrome/browser/autocomplete/history_url_provider.cc
index 3d394e6..a266201 100644
--- a/chrome/browser/autocomplete/history_url_provider.cc
+++ b/chrome/browser/autocomplete/history_url_provider.cc
@@ -36,6 +36,7 @@ HistoryURLProviderParams::HistoryURLProviderParams(
       input(input),
       trim_http(trim_http),
       cancel(false),
+      failed(false),
       languages(languages) {
 }
 
@@ -103,8 +104,10 @@ void HistoryURLProvider::ExecuteWithDB(history::HistoryBackend* backend,
                                        history::URLDatabase* db,
                                        HistoryURLProviderParams* params) {
   // We may get called with a NULL database if it couldn't be properly
-  // initialized.  In this case we just say the query is complete.
-  if (db && !params->cancel) {
+  // initialized.
+  if (!db) {
+    params->failed = true;
+  } else if (!params->cancel) {
     TimeTicks beginning_time = TimeTicks::Now();
 
     DoAutocomplete(backend, db, params);
@@ -222,9 +225,14 @@ void HistoryURLProvider::QueryComplete(
   if (params->cancel)
     return;  // Already set done_ when we canceled, no need to set it again.
 
+  // Don't modify |matches_| if the query failed, since it might have a default
+  // match in it, whereas |params->matches| will be empty.
+  if (!params->failed) {
+    matches_.swap(params->matches);
+    UpdateStarredStateOfMatches();
+  }
+
   done_ = true;
-  matches_.swap(params->matches);
-  UpdateStarredStateOfMatches();
   listener_->OnProviderUpdate(true);
 }
 
diff --git a/chrome/browser/autocomplete/history_url_provider.h b/chrome/browser/autocomplete/history_url_provider.h
index d133514..b87a2e3 100644
--- a/chrome/browser/autocomplete/history_url_provider.h
+++ b/chrome/browser/autocomplete/history_url_provider.h
@@ -101,6 +101,13 @@ struct HistoryURLProviderParams {
   // we run the extra queries, the lack of signaling is not a problem.
   bool cancel;
 
+  // Set by ExecuteWithDB() on the history thread when the query could not be
+  // performed because the history system failed to properly init the database.
+  // If this is set when the main thread is called back, it avoids changing
+  // |matches_| at all, so it won't delete the default match
+  // RunAutocompletePasses() creates.
+  bool failed;
+
   // List of matches written by the history thread.  We keep this separate list
   // to avoid having the main thread read the provider's matches while the
   // history thread is manipulating them.  The provider copies this list back