[Extensions] Fix InstalledLoader histograms to ignore component extenisons

Properly ignore component extensions in InstalledLoader.

Review URL: https://codereview.chromium.org/1114583002

Cr-Commit-Position: refs/heads/master@{#327317}

chrome/browser/extensions/installed_loader.cc

@@ -389,7 +389,7 @@ void InstalledLoader::RecordExtensionsMetrics() {
     // From now on, don't count component extensions, since they are only
     // extensions as an implementation detail. Continue to count unpacked
     // extensions for a few metrics.
-    if (location == Manifest::COMPONENT)
+    if (Manifest::IsComponentLocation(location))
       continue;
 
     // Histogram for non-webstore extensions overriding new tab page should