[Sync] Log UMA metrics for invalid BookmarkSpecifics due to invalid GUID

This is a follow-up patch to CL 1724669 [1], which adds to the
previously introduced UMA metrics keeping track of the reasons
BookmarkSpecifics are being deemed invalid. This patch logs as well the
case where an invalid GUID was found in the specifics.

Bug: 988451
Change-Id: Ifd52a28d4646b6333c13de63827aa33294b880b1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1811254Reviewed-by: Mohamed Amir Yosef <mamir@chromium.org>
Commit-Queue: Pauline Leitao <psivieroleitao@google.com>
Cr-Commit-Position: refs/heads/master@{#697962}

components/sync_bookmarks/bookmark_specifics_conversions.cc

@@ -37,8 +37,9 @@ enum class InvalidBookmarkSpecificsError {
   kIconURLWithoutFavicon = 2,
   kInvalidIconURL = 3,
   kNonUniqueMetaInfoKeys = 4,
+  kInvalidGUID = 5,
 
-  kMaxValue = kNonUniqueMetaInfoKeys,
+  kMaxValue = kInvalidGUID,
 };
 
 void LogInvalidSpecifics(InvalidBookmarkSpecificsError error) {
@@ -244,7 +245,8 @@ bool IsValidBookmarkSpecifics(const sync_pb::BookmarkSpecifics& specifics,
   }
   if (!base::IsValidGUID(specifics.guid()) && !specifics.guid().empty()) {
     DLOG(ERROR) << "Invalid bookmark: invalid GUID in the specifics.";
-    return false;
+    LogInvalidSpecifics(InvalidBookmarkSpecificsError::kInvalidGUID);
+    is_valid = false;
   }
   if (!is_folder) {
     if (!GURL(specifics.url()).is_valid()) {

tools/metrics/histograms/enums.xml

@@ -32396,6 +32396,7 @@ Called by update_gpu_driver_bug_workaround_entries.py.-->
   <int value="2" label="icon_url with missing favicon"/>
   <int value="3" label="Invalid icon_url"/>
   <int value="4" label="Non-unique meta_info keys"/>
+  <int value="5" label="Invalid GUID"/>
 </enum>
 
 <enum name="InvalidOriginReason">