Android: decouple mojo shell from the network service.

shell/android/apk/src/org/chromium/mojo_shell_apk/MojoMain.java

 // Copyright 2013 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.
 
 package org.chromium.mojo_shell_apk;
 
 import android.content.Context;
+import android.util.Log;
 
 import org.chromium.base.JNINamespace;
 
+import java.io.File;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
 /**
  * A placeholder class to call native functions.
  **/
 @JNINamespace("mojo")
 public class MojoMain {
+    private static final String TAG = "MojoMain";
+
+    // Directory where applications bundled with the shell will be extracted.
+    private static final String LOCAL_APP_DIRECTORY = "local_apps";
+    // Individual applications bundled with the shell as assets.
+    private static final String NETWORK_LIBRARY_APP = "network_service.mojo";
+
     /**
      * A guard flag for calling nativeInit() only once.
      **/
     private static boolean sInitialized = false;
 
     /**
+     * Deletes directories holding the temporary files. This should be called early on shell startup
+     * to clean up after the previous run.
+     */
+    static void clearTemporaryFiles(Context context) {
+        FileHelper.deleteRecursively(getLocalAppsDir(context));
+    }
+
+    /**
      * Initializes the native system.
      **/
     static void ensureInitialized(Context applicationContext, String[] parameters) {
         if (sInitialized)
             return;
-        List<String> parametersList = new ArrayList<String>();
-        // Program name.
-        parametersList.add("mojo_shell");
-        if (parameters != null) {
-            parametersList.addAll(Arrays.asList(parameters));
+
+        try {
+            FileHelper.extractFromAssets(applicationContext, NETWORK_LIBRARY_APP,
+                    getLocalAppsDir(applicationContext), false);
+
+            List<String> parametersList = new ArrayList<String>();
+            // Program name.
+            parametersList.add("mojo_shell");
+            if (parameters != null) {
+                parametersList.addAll(Arrays.asList(parameters));
+            }
+
+            nativeInit(applicationContext,
+                    parametersList.toArray(new String[parametersList.size()]),
+                    getLocalAppsDir(applicationContext).getAbsolutePath());
+            sInitialized = true;
+        } catch (Exception e) {
+            Log.e(TAG, "MojoMain initialization failed.", e);
+            throw new RuntimeException(e);
         }
-        nativeInit(applicationContext, parametersList.toArray(new String[parametersList.size()]));
-        sInitialized = true;
     }
 
     /**
      * Starts the specified application in the specified context.
      **/
     static void start(final String appUrl) {
         nativeStart(appUrl);
     }
 
+    private static File getLocalAppsDir(Context context) {
+        return context.getDir(LOCAL_APP_DIRECTORY, Context.MODE_PRIVATE);
+    }
+
     /**
      * Initializes the native system. This API should be called only once per process.
      **/
-    private static native void nativeInit(Context context, String[] parameters);
+    private static native void nativeInit(Context context, String[] parameters,
+            String bundledAppsDirectory);
 
     private static native void nativeStart(String appUrl);
 }