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

chrome/browser/extensions/extension_sync_data.cc

Index: chrome/browser/extensions/extension_sync_data.cc
diff --git a/chrome/browser/extensions/extension_sync_data.cc b/chrome/browser/extensions/extension_sync_data.cc
index 007887d2ce38b3f50a689ff63750eb6080379640..d01fa98a5c76c035b79d818b6186e224c77a5d65 100644
--- a/chrome/browser/extensions/extension_sync_data.cc
+++ b/chrome/browser/extensions/extension_sync_data.cc
@@ -96,17 +96,20 @@ void ExtensionSyncData::PopulateExtensionSpecifics(
 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();