Android: Record UMA for custom resources on startup.

Record UMA once during startup only for the browser process.

Bug: 768497
Change-Id: I24fa3eebe812ee4dc423390535e7b52ab8c6fcd1
Reviewed-on: https://chromium-review.googlesource.com/699697
Commit-Queue: Eric Stevenson <estevenson@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#506595}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: d0431dbd64a4c7f45125f9f23779cce1ec57d021

android/buildhooks/java/org/chromium/build/BuildHooksAndroid.java

@@ -62,4 +62,13 @@ public abstract class BuildHooksAndroid {
     }
 
     protected abstract void initCustomResourcesImpl(Context context);
+
+    /**
+     * Record custom resources related UMA. Requires native library to be loaded.
+     */
+    public static void maybeRecordResourceMetrics() {
+        sInstance.maybeRecordResourceMetricsImpl();
+    }
+
+    protected abstract void maybeRecordResourceMetricsImpl();
 }

android/buildhooks/java/org/chromium/build/BuildHooksAndroidImpl.java

@@ -35,4 +35,6 @@ public class BuildHooksAndroidImpl extends BuildHooksAndroid {
     }
 
     protected void initCustomResourcesImpl(Context context) {}
+
+    protected void maybeRecordResourceMetricsImpl() {}
 }