Add a do_not_sync pref to ExtensionPrefs.

extensions/browser/extension_prefs.cc

 // Copyright 2014 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 "extensions/browser/extension_prefs.h"
 
 #include <iterator>
 
 #include "base/command_line.h"
 #include "base/prefs/pref_notifier.h"
@@ skipping 178 matching lines @@
 
 // A preference indicating whether the extension is an ephemeral app.
 const char kPrefEphemeralApp[] = "ephemeral_app";
 
 // Am installation parameter bundled with an extension.
 const char kPrefInstallParam[] = "install_parameter";
 
 // A list of installed ids and a signature.
 const char kInstallSignature[] = "extensions.install_signature";
 
+// A boolean preference that indicates whether the extension should not be
+// synced. Default value is false.
+const char kPrefDoNotSync[] = "do_not_sync";
+
 // Provider of write access to a dictionary storing extension prefs.
 class ScopedExtensionPrefUpdate : public DictionaryPrefUpdate {
  public:
   ScopedExtensionPrefUpdate(PrefService* service,
                             const std::string& extension_id) :
     DictionaryPrefUpdate(service, pref_names::kExtensions),
     extension_id_(extension_id) {}
 
   virtual ~ScopedExtensionPrefUpdate() {
   }
@@ skipping 1529 matching lines @@
   }
   std::string install_time_str;
   if (!extension->GetString(kPrefInstallTime, &install_time_str))
     return base::Time();
   int64 install_time_i64 = 0;
   if (!base::StringToInt64(install_time_str, &install_time_i64))
     return base::Time();
   return base::Time::FromInternalValue(install_time_i64);
 }
 
+bool ExtensionPrefs::DoNotSync(const std::string& extension_id) const {
+  bool do_not_sync;
+  if (!ReadPrefAsBoolean(extension_id, kPrefDoNotSync, &do_not_sync))
+    return false;
+
+  return do_not_sync;
+}
+
 base::Time ExtensionPrefs::GetLastLaunchTime(
     const std::string& extension_id) const {
   const base::DictionaryValue* extension = GetExtensionPref(extension_id);
   if (!extension)
     return base::Time();
 
   std::string launch_time_str;
   if (!extension->GetString(kPrefLastLaunchTime, &launch_time_str))
     return base::Time();
   int64 launch_time_i64 = 0;
@@ skipping 365 matching lines @@
   if (!install_parameter.empty()) {
     extension_dict->Set(kPrefInstallParam,
                         new base::StringValue(install_parameter));
   }
   // We store prefs about LOAD extensions, but don't cache their manifest
   // since it may change on disk.
   if (!Manifest::IsUnpackedLocation(extension->location())) {
     extension_dict->Set(kPrefManifest,
                         extension->manifest()->value()->DeepCopy());
   }
+
+  // Only writes kPrefDoNotSync when it is not the default.
+  if (install_flags & kInstallFlagDoNotSync)
+    extension_dict->Set(kPrefDoNotSync, new base::FundamentalValue(true));

[not at google - send to devlin, 2014/06/13 20:01:22]

I think you need an else extension_dict->Remove(kPrefDoNotSync) call here? it
looks like this function is called when an extension updates, with its old pref
values... though I'm not totally sure.

[xiyuan, 2014/06/13 20:35:42]

Done. 

Yes, it's called for update as well. And fix a bug in extension_service.cc to
make sure update does not lose the bit.

 }
 
 void ExtensionPrefs::InitExtensionControlledPrefs(
     ExtensionPrefValueMap* value_map) {
   ExtensionIdList extension_ids;
   GetExtensions(&extension_ids);
 
   for (ExtensionIdList::iterator extension_id = extension_ids.begin();
        extension_id != extension_ids.end();
        ++extension_id) {
@@ skipping 83 matching lines @@
   extension_pref_value_map_->RegisterExtension(
       extension_id, install_time, is_enabled, is_incognito_enabled);
 
   FOR_EACH_OBSERVER(
       ExtensionPrefsObserver,
       observer_list_,
       OnExtensionRegistered(extension_id, install_time, is_enabled));
 }
 
 }  // namespace extensions