Add InvalidationStateTracker::Forget() to erase an entry from storage.

chrome/browser/sync/invalidations/invalidator_storage_unittest.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/sync/invalidations/invalidator_storage.h"
 
 #include "base/message_loop.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
@@ skipping 54 matching lines @@
 
   expected_max_versions[kAppNotificationsId_] = 3;
   storage.SetMaxVersion(kAppNotificationsId_, 3);
   EXPECT_EQ(expected_max_versions, storage.GetAllMaxVersions());
 
   expected_max_versions[kAppNotificationsId_] = 4;
   storage.SetMaxVersion(kAppNotificationsId_, 4);
   EXPECT_EQ(expected_max_versions, storage.GetAllMaxVersions());
 }
 
+// Forgetting an entry should cause that entry to be deleted.
+TEST_F(InvalidatorStorageTest, Forget) {
+  InvalidatorStorage storage(&pref_service_);
+  EXPECT_TRUE(storage.GetAllMaxVersions().empty());
+
+  InvalidationVersionMap expected_max_versions;
+  expected_max_versions[kBookmarksId_] = 2;
+  expected_max_versions[kPreferencesId_] = 5;
+  storage.SetMaxVersion(kBookmarksId_, 2);
+  storage.SetMaxVersion(kPreferencesId_, 5);
+  EXPECT_EQ(expected_max_versions, storage.GetAllMaxVersions());
+
+  expected_max_versions.erase(kPreferencesId_);
+  storage.Forget(kPreferencesId_);
+  EXPECT_EQ(expected_max_versions, storage.GetAllMaxVersions());
+}
+
 // Clearing the storage should result in an empty version map.
 TEST_F(InvalidatorStorageTest, Clear) {
   InvalidatorStorage storage(&pref_service_);
   EXPECT_TRUE(storage.GetAllMaxVersions().empty());
   EXPECT_TRUE(storage.GetInvalidationState().empty());
 
   storage.SetInvalidationState("test");
   EXPECT_EQ("test", storage.GetInvalidationState());
   {
     InvalidationVersionMap expected_max_versions;
@@ skipping 229 matching lines @@
 TEST_F(InvalidatorStorageTest, SetGetInvalidationState) {
   InvalidatorStorage storage(&pref_service_);
   const std::string mess("n\0tK\0\0l\344", 8);
   ASSERT_FALSE(IsStringUTF8(mess));
 
   storage.SetInvalidationState(mess);
   EXPECT_EQ(mess, storage.GetInvalidationState());
 }
 
 }  // namespace browser_sync