Adding missing values to the OfflinePrefetchItemErrorCode metrics enum

based on the existing values in PrefetchItemErrorCode
(prefetch_types.h).

Change-Id: I4fbf832aac68cc80bb3c33ab4135a7e40853ed05
Reviewed-on: https://chromium-review.googlesource.com/c/1297296
Commit-Queue: Carlos Knippschild <carlosk@chromium.org>
Reviewed-by: Dan H <harringtond@google.com>
Cr-Commit-Position: refs/heads/master@{#602176}

components/offline_pages/core/prefetch/prefetch_types.h

@@ -182,8 +182,8 @@ enum class PrefetchItemErrorCode {
   STALE_AT_DOWNLOADING = 1000,
   STALE_AT_IMPORTING = 1050,
   STALE_AT_UNKNOWN = 1100,
-  // The item was terminated due to not being concluded after being more than 7
-  // days in the pipeline.
+  // The item was terminated because it remained in the pipeline for more than
+  // 7 days.
   STUCK = 1150,
   // Exceeded maximum retries for get operation request.
   GET_OPERATION_MAX_ATTEMPTS_REACHED = 1200,

tools/metrics/histograms/enums.xml

@@ -37235,6 +37235,10 @@ Called by update_net_trust_anchors.py.-->
   <int value="1100" label="STALE_AT_UNKNOWN">
     Entry became stale at an unknown state.
   </int>
+  <int value="1150" label="STUCK">
+    The item was terminated because it remained in the pipeline for more than 7
+    days.
+  </int>
   <int value="1200" label="GET_OPERATION_MAX_ATTEMPTS_REACHED">
     Exceeding maximum retries for get operation request.
   </int>
@@ -37251,6 +37255,10 @@ Called by update_net_trust_anchors.py.-->
     The importing was not completed probably due to that Chrome was killed
     before it was done.
   </int>
+  <int value="1700" label="SUGGESTION_INVALIDATED">
+    The page suggestion is no longer valid, so the item no longer needs to be
+    downloaded.
+  </int>
 </enum>
 
 <enum name="OfflinePrefetchItemState">