[Checkstyle] Update class member variable names to match style guides.

tools/android/checkstyle/chromium-style-5.0.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.3//EN" "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
 
 <!--
   See installation instructions: https://sites.google.com/a/chromium.org/dev/checkstyle
 -->
 <module name="Checker">
   <property name="severity" value="warning"/>
   <property name="charset" value="UTF-8"/>
   <module name="TreeWalker">
@@ skipping 33 matching lines @@
     <module name="TypeName">
       <property name="severity" value="warning"/>
     </module>
     <module name="ConstantName">
       <property name="severity" value="warning"/>
       <property name="format" value="^([A-Z][A-Z0-9]*(_[A-Z0-9]+)*)|(s[A-Z][a-zA-Z0-9]*)$"/>
       <message key="name.invalidPattern" value="Static final field names must either be all caps (e.g. int HEIGHT_PX) for 'true' constants, or start with s (e.g. AtomicInteger sNextId or Runnable sSuspendTask) for fields with mutable state or that don't 'feel' like constants."/>
     </module>
     <!-- Non-public, non-static field names start with m. -->
     <module name="MemberName">
+        <property name="severity" value="error"/>
         <property name="format" value="^m[A-Z][a-zA-Z0-9]*$"/>
         <property name="applyToPublic" value="false"/>
         <message key="name.invalidPattern" value="Non-public, non-static field names start with m."/>
     </module>
     <!-- Static field names start with s. -->
     <module name="StaticVariableName">
         <property name="format" value="^s[A-Z][a-zA-Z0-9]*$"/>
         <property name="applyToPublic" value="false"/>
         <message key="name.invalidPattern" value="Static field names start with s."/>
     </module>
@@ skipping 85 matching lines @@
   <module name="RegexpSingleline">
     <property name="severity" value="error"/>
     <property name="format" value="[ \t]+$"/>
     <property name="message" value="Trailing whitespace"/>
     </module>
   <module name="RegexpHeader">
     <property name="severity" value="error"/>
     <property name="header" value="^// Copyright 20\d\d The Chromium Authors. All rights reserved.$\n^// Use of this source code is governed by a BSD-style license that can be$\n^// found in the LICENSE file.$"/>
   </module>
 </module>