Remove the obsolete MinidumpDirectoryObserver experiment.

chrome/android/java/src/org/chromium/chrome/browser/crash/MinidumpDirectoryObserver.java

 // Copyright 2016 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.chrome.browser.crash;
 
 import android.content.Context;
 import android.content.Intent;
 import android.os.Build;
 import android.os.FileObserver;
 
 import org.chromium.base.ContextUtils;
 import org.chromium.base.Log;
 import org.chromium.base.PathUtils;
 import org.chromium.base.metrics.RecordUserAction;
 
 import java.io.File;
 
 /**
  * The FileObserver to monitor the minidump directory.
  */
 public class MinidumpDirectoryObserver extends FileObserver {
 
     private static final String TAG = "MinidumpDirObserver";
     private static Context sContext = ContextUtils.getApplicationContext();
 
-    public static final String MINIDUMP_EXPERIMENT_NAME = "MinidumpDirectoryObserver";
-
     public MinidumpDirectoryObserver() {
         // The file observer detects MOVED_TO for child processes.
         super(new File(PathUtils.getCacheDirectory(sContext),
                 CrashFileManager.CRASH_DUMP_DIR).toString(), FileObserver.MOVED_TO);
     }
 
     /**
      *  When a minidump is detected, upload it to Google crash server
      */
     @Override
@@ skipping 10 matching lines @@
                 // find our own crash uploading service. Ignore a SecurityException here on older
                 // OS versions since the crash will eventually get uploaded on next start.
                 // crbug/542533
                 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                     throw e;
                 }
             }
         }
     }
 }