Android: Add version suffix to extracted .pak files

base/android/java/src/org/chromium/base/BuildInfo.java

 // Copyright 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.
 
 package org.chromium.base;
 
 import android.content.Context;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
@@ skipping 91 matching lines @@
             msg = "";
             if (pi.versionName != null) {
                 msg = pi.versionName;
             }
         } catch (NameNotFoundException e) {
             Log.d(TAG, msg);
         }
         return msg;
     }
 
+    /** Returns a string that is different each time the apk changes. */
+    @CalledByNative
+    public static String getExtractedFileSuffix() {
+        PackageManager pm = ContextUtils.getApplicationContext().getPackageManager();
+        try {
+            PackageInfo pi =
+                    pm.getPackageInfo(ContextUtils.getApplicationContext().getPackageName(), 0);
+            // Use lastUpdateTime when developing locally, since versionCode does not normally
+            // change in this case.
+            long version = pi.versionCode > 10 ? pi.versionCode : pi.lastUpdateTime;
+            return "@" + Long.toHexString(version);
+        } catch (PackageManager.NameNotFoundException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     @CalledByNative
     public static String getPackageLabel() {
         // Third-party code does disk read on the getApplicationInfo call. http://crbug.com/614343
         StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads();
         try {
             PackageManager packageManager =
                     ContextUtils.getApplicationContext().getPackageManager();
             ApplicationInfo appInfo = packageManager.getApplicationInfo(
                     getPackageName(), PackageManager.GET_META_DATA);
             CharSequence label = packageManager.getApplicationLabel(appInfo);
@@ skipping 40 matching lines @@
 
     /**
      * @return Whether the current app targets the SDK for at least O
      */
     public static boolean targetsAtLeastO(Context appContext) {
         return isAtLeastO()
                 && appContext.getApplicationInfo().targetSdkVersion
                 == Build.VERSION_CODES.CUR_DEVELOPMENT;
     }
 }