Wait for the history backend to load, which makes AutocompleteBrowserTest.Autocomplete not flaky.

chrome/browser/autocomplete/autocomplete_browsertest.cc

 // Copyright (c) 2009 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/autocomplete.h"
 #include "chrome/browser/autocomplete/autocomplete_edit.h"
 #include "chrome/browser/autocomplete/autocomplete_edit_view.h"
 #include "chrome/browser/autocomplete/autocomplete_popup_model.h"
 #include "chrome/browser/browser.h"
 #include "chrome/browser/browser_window.h"
+#include "chrome/browser/history/history.h"
 #include "chrome/browser/location_bar.h"
+#include "chrome/browser/profile.h"
+#include "chrome/common/notification_registrar.h"
+#include "chrome/common/notification_service.h"
+#include "chrome/common/notification_type.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/in_process_browser_test.h"
 #include "chrome/test/ui_test_utils.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 std::wstring AutocompleteResultAsString(const AutocompleteResult& result) {
   std::wstring output(StringPrintf(L"{%d} ", result.size()));
   for (size_t i = 0; i < result.size(); ++i) {
     AutocompleteMatch match = result.match_at(i);
     std::wstring provider_name(ASCIIToWide(match.provider->name()));
     output.append(StringPrintf(L"[\"%ls\" by \"%ls\"] ",
                                match.contents.c_str(),
                                provider_name.c_str()));
   }
   return output;
 }
 
 }  // namespace
 
-class AutocompleteBrowserTest : public InProcessBrowserTest {
+class AutocompleteBrowserTest : public InProcessBrowserTest,
+                                public NotificationObserver {
  protected:
   LocationBar* GetLocationBar() const {
     return browser()->window()->GetLocationBar();
   }
 
   AutocompleteController* GetAutocompleteController() const {
     return GetLocationBar()->location_entry()->model()->popup_model()->
         autocomplete_controller();
   }
+
+  void WaitForHistoryBackendToLoad() {
+    HistoryService* history_service =
+        browser()->profile()->GetHistoryService(Profile::EXPLICIT_ACCESS);
+    if (!history_service->backend_loaded()) {
+      NotificationRegistrar registrar;
+      registrar.Add(this, NotificationType::HISTORY_LOADED,
+                    NotificationService::AllSources());
+      ui_test_utils::RunMessageLoop();
+    }
+  }
+
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details) {
+    DCHECK(type == NotificationType::HISTORY_LOADED);
+    MessageLoop::current()->Quit();
+  }
+
 };
 
 IN_PROC_BROWSER_TEST_F(AutocompleteBrowserTest, Basic) {
   LocationBar* location_bar = GetLocationBar();
 
   EXPECT_EQ(std::wstring(), location_bar->GetInputString());
   EXPECT_EQ(UTF8ToWide(chrome::kAboutBlankURL),
             location_bar->location_entry()->GetText());
   // TODO(phajdan.jr): check state of IsSelectAll when it's consistent across
   // platforms.
@@ skipping 21 matching lines @@
   location_bar->location_entry()->SetUserText(L"chrome");
   location_bar->Revert();
 
   EXPECT_EQ(std::wstring(), location_bar->GetInputString());
   EXPECT_EQ(UTF8ToWide(chrome::kAboutBlankURL),
             location_bar->location_entry()->GetText());
   EXPECT_FALSE(location_bar->location_entry()->IsSelectAll());
 }
 
 IN_PROC_BROWSER_TEST_F(AutocompleteBrowserTest, Autocomplete) {
+  // The results depend on the history backend being loaded. Make sure it is
+  // loaded so that the autocomplete results are consistent.
+  WaitForHistoryBackendToLoad();
+
   LocationBar* location_bar = GetLocationBar();
   AutocompleteController* autocomplete_controller = GetAutocompleteController();
 
   {
     autocomplete_controller->Start(L"chrome", std::wstring(),
                                    true, false, true);
 
     EXPECT_TRUE(autocomplete_controller->done());
     EXPECT_EQ(std::wstring(), location_bar->GetInputString());
     EXPECT_EQ(std::wstring(), location_bar->location_entry()->GetText());
     EXPECT_TRUE(location_bar->location_entry()->IsSelectAll());
     const AutocompleteResult& result = autocomplete_controller->result();
     ASSERT_EQ(1U, result.size()) << AutocompleteResultAsString(result);
     AutocompleteMatch match = result.match_at(0);
     EXPECT_EQ(AutocompleteMatch::SEARCH_WHAT_YOU_TYPED, match.type);
     EXPECT_FALSE(match.deletable);
   }
 
   {
     location_bar->Revert();
 
     EXPECT_EQ(std::wstring(), location_bar->GetInputString());
     EXPECT_EQ(UTF8ToWide(chrome::kAboutBlankURL),
               location_bar->location_entry()->GetText());
     EXPECT_FALSE(location_bar->location_entry()->IsSelectAll());
     const AutocompleteResult& result = autocomplete_controller->result();
     EXPECT_TRUE(result.empty()) << AutocompleteResultAsString(result);
   }
 }