Fix the gdb path for NDK-r8b.

content/shell/android/java/content_shell_apk.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <!--
   Copyright (c) 2012 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.
 -->
 <project name="ContentShell" default="debug" basedir=".">
   <description>
     Building ContentShell.apk
   </description>
   <import file="../../../../build/android/ant/common.xml"/>
   <import file="../../../../build/android/ant/sdk-targets.xml"/>
 
   <!-- Convert the buildtype to lowercase. E.g Debug -> debug, Release -> release.  -->
   <script language="javascript">
     project.setProperty("configuration.name",
                         project.getProperty("CONFIGURATION_NAME").toLowerCase())
   </script>
   <property-value name="target.abi" value="${APP_ABI}"/>
   <property-location name="out.dir" location="${PRODUCT_DIR}/content_shell"
       check-exists="false"/>
   <property name="resource.absolute.dir" value="../res"/>
   <property name="gen.absolute.dir" value="${out.dir}/gen"/>
   <property name="jar.libs.dir" value="${out.dir}/java/libs"/>
   <path id="native.libs.gdbserver">
-    <fileset file="${toolchain.dir}/../../gdbserver"/>
+    <fileset file="${android.gdbserver}"/>
   </path>
   <property name="native.libs.absolute.dir" location="${out.dir}/libs"/>
   <property name="asset.absolute.dir" location="${out.dir}/assets"/>
 
   <path id="out.dex.jar.input.ref">
     <fileset file="${out.dir}/java/libs/chromium_content.jar"/>
     <fileset file="${out.dir}/java/libs/chromium_net.jar"/>
     <fileset file="${out.dir}/java/libs/chromium_base.jar"/>
     <fileset file="${out.dir}/java/libs/chromium_media.jar"/>
   </path>
@@ skipping 28 matching lines @@
       </then>
     </if>
   </target>
 
   <!-- Classpath for javac -->
   <path id="javac.custom.classpath">
     <path refid="out.dex.jar.input.ref"/>
   </path>
   <import file="${sdk.dir}/tools/ant/build.xml"/>
 </project>