Add Proguard option to gyp template.

build/android/ant/chromium-apk.xml

Index: build/android/ant/chromium-apk.xml
diff --git a/build/android/ant/chromium-apk.xml b/build/android/ant/chromium-apk.xml
index 2779a5e6c086fad4bed071a035149dab69ab3f0b..f848c86cde95ec89318ace3a0e1cd5cf083b43be 100644
--- a/build/android/ant/chromium-apk.xml
+++ b/build/android/ant/chromium-apk.xml
@@ -28,6 +28,13 @@
   <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}">
@@ -39,13 +46,13 @@
       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"/>