Whitelist Highlights apps for getIsCrashReportingEnabled

The Highlights app is part of Chrome OS Demo Mode. It will use
chrom.metricsPrivate.getIsCrashReportingEnabled() to enable/disable
Google Analytics reporting, similar to other Chrome apps.

There are 2 versions of this app, thus 2 entries.

Bug: 819404
Change-Id: I023880eac23c332afe1fb80942c7d9f737cb369d
Reviewed-on: https://chromium-review.googlesource.com/1179370Reviewed-by: Toni Baržić <tbarzic@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Michael Giuffrida <michaelpg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584305}

extensions/common/api/_api_features.json

@@ -308,7 +308,9 @@
       "2B6C6A4A5940017146F3E58B7F90116206E84685",  // http://crbug.com/642141
       "B6C2EFAB3EC3BF6EF03701408B6B09A67B2D0069",  // http://crbug.com/642141
       "96FF2FFA5C9173C76D47184B3E86D267B37781DE",  // http://crbug.com/642141
-      "0136FCB13DB29FD5CD442F56E59E53B61F1DF96F"   // http://crbug.com/642141
+      "0136FCB13DB29FD5CD442F56E59E53B61F1DF96F",  // http://crbug.com/642141
+      "46578A13607D38F1DC8E280C4F499FB0A2F9565C",  // http://crbug.com/819404
+      "898FB5A39687D210766B8998BA4530B99C9E6586"   // http://crbug.com/819404
     ]
   },
   "mimeHandlerPrivate": {