Revert "Add UMA Histogram Manager to Cronet."

components/cronet/android/java/src/org/chromium/net/HistogramManager.java

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-package org.chromium.net;
-
-import org.chromium.base.JNINamespace;
-
-/**
- * Controls UMA histograms.
- */
-@JNINamespace("cronet")
-public final class HistogramManager {
-    public HistogramManager() {
-    }
-
-    /**
-     * Get histogram deltas serialized as protobuf.
-     */
-    public byte[] getHistogramDeltas() {
-        return nativeGetHistogramDeltas();
-    }
-
-    private native byte[] nativeGetHistogramDeltas();
-}