Add Proguard option to gyp template.

build/android/ant/chromium-apk.xml

 <!--
   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 default="debug">
   <property name="ant.project.name" value="${APK_NAME}"/>
 
   <description>
     Building ${ant.project.name}.apk
@@ skipping 10 matching lines @@
     <filelist files="${ADDITIONAL_SRC_DIRS}"/>
     <filelist files="${GENERATED_SRC_DIRS}"/>
   </path>
 
   <property-value name="target.abi" value="${APP_ABI}"/>
   <property name="resource.absolute.dir" value="${RESOURCE_DIR}"/>
   <property-value name="gen.absolute.dir" value="${out.dir}/gen"/>
   <property-location name="native.libs.absolute.dir" location="${out.dir}/libs"
       check-exists="false"/>
 
+  <property-value name="version.code" value="${APP_MANIFEST_VERSION_CODE}"/>
+  <property-value name="version.name" value="${APP_MANIFEST_VERSION_NAME}"/>
+
+  <property name="proguard.config" value="${PROGUARD_FLAGS}"/>
+  <property name="proguard.enabled" value="${PROGUARD_ENABLED}"/>
+  <!-- TODO(shashishekhar): Enable emma and code-coverage filters. -->
+
   <condition property="asset.absolute.dir"
       value="${out.dir}/assets"
       else="${ASSET_DIR}">
     <equals arg1="${ASSET_DIR}" arg2=""/>
   </condition>
 
   <!-- Set the output directory for the final apk to the ${apks.dir}. -->
   <property-location name="out.final.file"
       location="${apks.dir}/${ant.project.name}-debug.apk"
       check-exists="false"/>
 
-  <path id="out.dex.jar.input.ref">
+  <!-- Classpath for javac -->
+  <path id="javac.custom.classpath">
     <filelist files="${INPUT_JARS_PATHS}"/>
   </path>
 
-  <!-- Classpath for javac -->
-  <path id="javac.custom.classpath">
-    <path refid="out.dex.jar.input.ref"/>
+  <path id="out.dex.jar.input.ref">
+    <path refid="javac.custom.classpath"/>
   </path>
 
   <import file="sdk-targets.xml"/>
   <import file="${sdk.dir}/tools/ant/build.xml"/>
 </project>