Remove deprecated UrlRequestContextConfig & HttpUrlRequestFactoryConfig

components/cronet/android/api/build.xml

 <project>
   <target name="doc" description="generate documentation">
       <javadoc destdir="${doc.dir}"
                overview="${overview}"
                bootclasspath="../../../../third_party/android_tools/sdk/platforms/android-23/android.jar:../../../../third_party/android_tools/sdk/extras/android/support/annotations/android-support-annotations.jar:${lib.java.dir}/cronet_javadoc_classpath.jar"
                docletpath="../../../../buildtools/android/doclava/jsilver.jar:../../../../buildtools/android/doclava/doclava.jar"
                >
         <fileset dir="${source.dir}" defaultexcludes="yes">
           <include name="**/*.java"/>
           <!-- exclude legacy API -->
           <exclude name="**/Chromium*.java"/>
           <exclude name="**/ChunkedWritableByteChannel*.java"/>
           <exclude name="**/HttpUrl*.java"/>
           <exclude name="**/ResponseTooLargeException.java"/>
-          <exclude name="**/UrlRequestContextConfig.java"/>
           <!-- This file is removed but it still appears in the checkout of one bot. See crbug.com/637887 -->
           <!-- TODO(xunjieli): Remove this. -->
           <exclude name="**/RequestFinishedListener.java"/>
         </fileset>
         <doclet name="com.google.doclava.Doclava">
           <param name="-title" /><param name="Cronet API"/>
           <!-- federation -->
           <param name="-federate" /><param name="Android"/>
           <param name="https://developer.android.com/"/>
           <param name="-federationapi"/><param name="Android"/>
           <param name="../../../../buildtools/android/doclava/current.txt"/>
         </doclet>
       </javadoc>
   </target>
 </project>