Fix for Bug 50726 "Save extension list and "winning" prefs from extensions"

chrome/browser/extensions/test_extension_prefs.cc

 // Copyright (c) 2010 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/extensions/test_extension_prefs.h"
 
 #include "base/file_util.h"
 #include "base/message_loop.h"
 #include "base/scoped_ptr.h"
 #include "base/values.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/extensions/extension_prefs.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prefs/pref_value_store.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/json_pref_store.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-TestExtensionPrefs::TestExtensionPrefs() {
+// Mock ExtensionPrefs class with artificial clock to guarantee that no two
+// extensions get the same installation time stamp and we can reliably
+// assert the installation order in the tests below.
+class MockExtensionPrefs : public ExtensionPrefs {
+ public:
+  MockExtensionPrefs(PrefService* prefs, const FilePath& root_dir_)
+    : ExtensionPrefs(prefs, root_dir_),
+      currentTime(base::Time::Now())
+  {}
+  ~MockExtensionPrefs() {}
+
+ protected:
+  mutable base::Time currentTime;
+
+  virtual base::Time GetCurrentTime() const {
+    currentTime += base::TimeDelta::FromSeconds(10);
+    return currentTime;
+  }
+};
+
+TestExtensionPrefs::TestExtensionPrefs() : pref_service_(NULL) {
   EXPECT_TRUE(temp_dir_.CreateUniqueTempDir());
   preferences_file_ = temp_dir_.path().AppendASCII("Preferences");
   extensions_dir_ = temp_dir_.path().AppendASCII("Extensions");
   EXPECT_TRUE(file_util::CreateDirectory(extensions_dir_));
 
   RecreateExtensionPrefs();
 }
 
 TestExtensionPrefs::~TestExtensionPrefs() {}
 
 void TestExtensionPrefs::RecreateExtensionPrefs() {
+  // We persist and reload the PrefService's PrefStores because this process
+  // deletes all empty dictionaries. The ExtensionPrefs implementation
+  // needs to be able to handle this situation.
   if (pref_service_.get()) {
     // The PrefService writes its persistent file on the file thread, so we
     // need to wait for any pending I/O to complete before creating a new
     // PrefService.
     MessageLoop file_loop;
     BrowserThread file_thread(BrowserThread::FILE, &file_loop);
     pref_service_->SavePersistentPrefs();
     file_loop.RunAllPending();
   }
 
   // Create a |PrefService| instance that contains only user defined values.
   pref_service_.reset(PrefService::CreateUserPrefService(preferences_file_));
   ExtensionPrefs::RegisterUserPrefs(pref_service_.get());
-  prefs_.reset(new ExtensionPrefs(pref_service_.get(), temp_dir_.path()));
+  prefs_.reset(new MockExtensionPrefs(pref_service_.get(), temp_dir_.path()));
 }
 
 scoped_refptr<Extension> TestExtensionPrefs::AddExtension(std::string name) {
   DictionaryValue dictionary;
   dictionary.SetString(extension_manifest_keys::kName, name);
   dictionary.SetString(extension_manifest_keys::kVersion, "0.1");
   return AddExtensionWithManifest(dictionary, Extension::INTERNAL);
 }
 
 scoped_refptr<Extension> TestExtensionPrefs::AddExtensionWithManifest(
@@ skipping 12 matching lines @@
   const bool kInitialIncognitoEnabled = false;
   prefs_->OnExtensionInstalled(extension, Extension::ENABLED,
                                kInitialIncognitoEnabled);
   return extension;
 }
 
 std::string TestExtensionPrefs::AddExtensionAndReturnId(std::string name) {
   scoped_refptr<Extension> extension(AddExtension(name));
   return extension->id();
 }