Get more useful LOG(FATAL) messages from ExtensionSyncData to help diagnose crashes.

chrome/browser/extensions/extension_sync_data.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/extensions/extension_sync_data.h"
 
 #include "base/logging.h"
 #include "chrome/browser/extensions/app_sync_data.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "components/crx_file/id_util.h"
@@ skipping 78 matching lines @@
   specifics->set_remote_install(remote_install_);
   if (all_urls_enabled_ != BOOLEAN_UNSET)
     specifics->set_all_urls_enabled(all_urls_enabled_ == BOOLEAN_TRUE);
   specifics->set_installed_by_custodian(installed_by_custodian_);
   specifics->set_name(name_);
 }
 
 void ExtensionSyncData::PopulateFromExtensionSpecifics(
     const sync_pb::ExtensionSpecifics& specifics) {
   if (!crx_file::id_util::IdIsValid(specifics.id())) {
-    LOG(FATAL) << "Attempt to sync bad ExtensionSpecifics.";
+    LOG(FATAL) << "Attempt to sync bad ExtensionSpecifics: bad ID "
+               << specifics.id() << ".";

[Devlin, 2015/02/21 17:33:35]

If it was me, I'd probably make a LogExtensionSpecifics() method that printed
out the id, version, update url, and name.  I'm just thinking that if we find a
bad extension id, that in and of itself may not help much (though it may).

   }
 
   Version specifics_version(specifics.version());
   if (!specifics_version.IsValid())
-    LOG(FATAL) << "Attempt to sync bad ExtensionSpecifics.";
+    LOG(FATAL) << "Attempt to sync bad ExtensionSpecifics: bad version "
+               << specifics.version() << ".";
 
   // The update URL must be either empty or valid.
   GURL specifics_update_url(specifics.update_url());
   if (!specifics_update_url.is_empty() && !specifics_update_url.is_valid()) {
-    LOG(FATAL) << "Attempt to sync bad ExtensionSpecifics.";
+    LOG(FATAL) << "Attempt to sync bad ExtensionSpecifics: bad update URL "
+               << specifics.update_url() << ".";
   }
 
   id_ = specifics.id();
   update_url_ = specifics_update_url;
   version_ = specifics_version;
   enabled_ = specifics.enabled();
   incognito_enabled_ = specifics.incognito_enabled();
   if (specifics.has_all_urls_enabled()) {
     all_urls_enabled_ =
         specifics.all_urls_enabled() ? BOOLEAN_TRUE : BOOLEAN_FALSE;
@@ skipping 16 matching lines @@
   const sync_pb::EntitySpecifics& entity_specifics = sync_data.GetSpecifics();
 
   if (entity_specifics.has_extension()) {
     PopulateFromExtensionSpecifics(entity_specifics.extension());
   } else {
     LOG(FATAL) << "Attempt to sync bad EntitySpecifics.";
   }
 }
 
 }  // namespace extensions