[iOS] Remove TabModelList from metrics client

This CL removes use of TabModelList from the metrics services manager
client.

Since this was the only use case for TabModelList's
IsOffTheRecordSessionActive(), that logic is just reproduced in a static
method for this class, using BrowserList.

Bug: 1050142
Change-Id: I52090af91a3088cfe8e216c6c0d60f94ec292ce4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2120412
Commit-Queue: Mark Cogan <[email protected]>
Reviewed-by: Mohammad Refaat <[email protected]>
Reviewed-by: Olivier Robin <[email protected]>
Cr-Commit-Position: refs/heads/master@{#753256}
diff --git a/ios/chrome/browser/metrics/BUILD.gn b/ios/chrome/browser/metrics/BUILD.gn
index 1d875cf..756a763 100644
--- a/ios/chrome/browser/metrics/BUILD.gn
+++ b/ios/chrome/browser/metrics/BUILD.gn
@@ -72,7 +72,8 @@
     "//ios/chrome/browser/browser_state",
     "//ios/chrome/browser/crash_report",
     "//ios/chrome/browser/google",
-    "//ios/chrome/browser/history:history",
+    "//ios/chrome/browser/history",
+    "//ios/chrome/browser/main:public",
     "//ios/chrome/browser/signin",
     "//ios/chrome/browser/sync",
     "//ios/chrome/browser/tabs",