Convert RendererTerminated metrics to UKM

Design doc:
https://docs.google.com/document/d/1eIPyR75iA_oDPdq8APAd8eIN1kqkjfw-e9zl2bKMxp8/edit#heading=h.qjpzx8d6k7t5

Bug: 685649
Change-Id: I7bcf6708a06055b19cb17aaf9060f9014ae68500
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1660858
Commit-Queue: Olivier Robin <[email protected]>
Reviewed-by: Robert Kaplow (slow) <[email protected]>
Reviewed-by: Eugene But <[email protected]>
Cr-Commit-Position: refs/heads/master@{#671298}
diff --git a/ios/chrome/browser/metrics/BUILD.gn b/ios/chrome/browser/metrics/BUILD.gn
index 75424c4c1..99babea 100644
--- a/ios/chrome/browser/metrics/BUILD.gn
+++ b/ios/chrome/browser/metrics/BUILD.gn
@@ -154,6 +154,7 @@
     "//ios/chrome/browser/ui/util",
     "//ios/chrome/browser/web_state_list",
     "//ios/web",
+    "//services/metrics/public/cpp:ukm_builders",
     "//ui/base",
     "//url",
   ]