Add chrome://history to WebUI.CreatedForUrl histogram values.

BUG=None
NO_DEPENDENCY_CHECKS=true

Review-Url: https://codereview.chromium.org/2418043003
Cr-Commit-Position: refs/heads/master@{#427006}

tools/metrics/histograms/histograms.xml

@@ -103028,6 +103028,7 @@ value.
 <enum name="WebUIUrlHashes" type="int">
   <int value="-2103246641" label="chrome://signin-internals/"/>
   <int value="-2034706497" label="chrome://net-internals/"/>
+  <int value="-1911971715" label="chrome://history/"/>
   <int value="-1887206190" label="chrome://nfc-debug/"/>
   <int value="-1808179141" label="chrome://password-manager-internals/"/>
   <int value="-1743341803" label="chrome://bookmarks/"/>