Fix "unreachable code" warnings (MSVC warning 4702), misc. edition.

sync/syncable/model_type.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 "sync/internal_api/public/base/model_type.h"
 
 #include "base/strings/string_split.h"
 #include "base/values.h"
 #include "sync/protocol/app_notification_specifics.pb.h"
 #include "sync/protocol/app_setting_specifics.pb.h"
@@ skipping 117 matching lines @@
   ModelTypeSet protocol_types = ProtocolTypes();
   for (ModelTypeSet::Iterator iter = protocol_types.First(); iter.Good();
        iter.Inc()) {
     if (GetSpecificsFieldNumberFromModelType(iter.Get()) == field_number)
       return iter.Get();
   }
   return UNSPECIFIED;
 }
 
 int GetSpecificsFieldNumberFromModelType(ModelType model_type) {
-  if (!ProtocolTypes().Has(model_type)) {
-    NOTREACHED() << "Only protocol types have field values.";
-    return 0;
-  }
+  DCHECK(ProtocolTypes().Has(model_type))

[darin (slow to review), 2014/03/18 08:07:30]

Aren't you tossing out the early return by going with DCHECK here?

[Peter Kasting, 2014/03/18 18:59:15]

Yes, per the style guide's "Don't handle DCHECK failure" rule. 
DCHECK/NOTREACHED mean we can never violate the condition under any
circumstances, even exceptional ones.  If we actually need the early return, we
shouldn't be using these in the first place, we should use a simple conditional.

+      << "Only protocol types have field values.";
   switch (model_type) {
     case BOOKMARKS:
       return sync_pb::EntitySpecifics::kBookmarkFieldNumber;
-      break;
     case PASSWORDS:
       return sync_pb::EntitySpecifics::kPasswordFieldNumber;
-      break;
     case PREFERENCES:
       return sync_pb::EntitySpecifics::kPreferenceFieldNumber;
-      break;
     case AUTOFILL:
       return sync_pb::EntitySpecifics::kAutofillFieldNumber;
-      break;
     case AUTOFILL_PROFILE:
       return sync_pb::EntitySpecifics::kAutofillProfileFieldNumber;
-      break;
     case THEMES:
       return sync_pb::EntitySpecifics::kThemeFieldNumber;
-      break;
     case TYPED_URLS:
       return sync_pb::EntitySpecifics::kTypedUrlFieldNumber;
-      break;
     case EXTENSIONS:
       return sync_pb::EntitySpecifics::kExtensionFieldNumber;
-      break;
     case NIGORI:
       return sync_pb::EntitySpecifics::kNigoriFieldNumber;
-      break;
     case SEARCH_ENGINES:
       return sync_pb::EntitySpecifics::kSearchEngineFieldNumber;
-      break;
     case SESSIONS:
       return sync_pb::EntitySpecifics::kSessionFieldNumber;
-      break;
     case APPS:
       return sync_pb::EntitySpecifics::kAppFieldNumber;
-      break;
     case APP_LIST:
       return sync_pb::EntitySpecifics::kAppListFieldNumber;
-      break;
     case APP_SETTINGS:
       return sync_pb::EntitySpecifics::kAppSettingFieldNumber;
-      break;
     case EXTENSION_SETTINGS:
       return sync_pb::EntitySpecifics::kExtensionSettingFieldNumber;
-      break;
     case APP_NOTIFICATIONS:
       return sync_pb::EntitySpecifics::kAppNotificationFieldNumber;
-      break;
     case HISTORY_DELETE_DIRECTIVES:
       return sync_pb::EntitySpecifics::kHistoryDeleteDirectiveFieldNumber;
     case SYNCED_NOTIFICATIONS:
       return sync_pb::EntitySpecifics::kSyncedNotificationFieldNumber;
     case SYNCED_NOTIFICATION_APP_INFO:
       return sync_pb::EntitySpecifics::kSyncedNotificationAppInfoFieldNumber;
     case DEVICE_INFO:
       return sync_pb::EntitySpecifics::kDeviceInfoFieldNumber;
-      break;
     case EXPERIMENTS:
       return sync_pb::EntitySpecifics::kExperimentsFieldNumber;
-      break;
     case PRIORITY_PREFERENCES:
       return sync_pb::EntitySpecifics::kPriorityPreferenceFieldNumber;
-      break;
     case DICTIONARY:
       return sync_pb::EntitySpecifics::kDictionaryFieldNumber;
-      break;
     case FAVICON_IMAGES:
       return sync_pb::EntitySpecifics::kFaviconImageFieldNumber;
     case FAVICON_TRACKING:
       return sync_pb::EntitySpecifics::kFaviconTrackingFieldNumber;
     case MANAGED_USER_SETTINGS:
       return sync_pb::EntitySpecifics::kManagedUserSettingFieldNumber;
     case MANAGED_USERS:
       return sync_pb::EntitySpecifics::kManagedUserFieldNumber;
     case MANAGED_USER_SHARED_SETTINGS:
       return sync_pb::EntitySpecifics::kManagedUserSharedSettingFieldNumber;
     case ARTICLES:
       return sync_pb::EntitySpecifics::kArticleFieldNumber;
     default:
       NOTREACHED() << "No known extension for model type.";
       return 0;
   }
-  NOTREACHED() << "Needed for linux_keep_shadow_stacks because of "
-               << "http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20681";
-  return 0;
 }
 
 FullModelTypeSet ToFullModelTypeSet(ModelTypeSet in) {
   FullModelTypeSet out;
   for (ModelTypeSet::Iterator i = in.First(); i.Good(); i.Inc()) {
     out.Put(i.Get());
   }
   return out;
 }
 
@@ skipping 803 matching lines @@
 
 bool IsRealDataType(ModelType model_type) {
   return model_type >= FIRST_REAL_MODEL_TYPE && model_type < MODEL_TYPE_COUNT;
 }
 
 bool IsActOnceDataType(ModelType model_type) {
   return model_type == HISTORY_DELETE_DIRECTIVES;
 }
 
 }  // namespace syncer