🎋 Android: Use both versionCode and lastUpdateTime for change-detection

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

Index: base/android/java/src/org/chromium/base/ResourceExtractor.java
diff --git a/base/android/java/src/org/chromium/base/ResourceExtractor.java b/base/android/java/src/org/chromium/base/ResourceExtractor.java
index 807fbb3c693725384f25e810bea4c2d11c275d2b..898b4910bcf9feb6313bc69d69446c77064a81a2 100644
--- a/base/android/java/src/org/chromium/base/ResourceExtractor.java
+++ b/base/android/java/src/org/chromium/base/ResourceExtractor.java
@@ -150,10 +150,14 @@ public class ResourceExtractor {
         private long getApkVersion() {
             PackageManager pm = ContextUtils.getApplicationContext().getPackageManager();
             try {
-                // More appropriate would be versionCode, but it doesn't change while developing.
+                // Use lastUpdateTime since versionCode does not change when developing locally,
+                // but also use versionCode since it is possible for Chrome to be updated without
+                // the lastUpdateTime being changed (http://crbug.org/673458).
                 PackageInfo pi =
                         pm.getPackageInfo(ContextUtils.getApplicationContext().getPackageName(), 0);
-                return pi.lastUpdateTime;
+                // Xor'ing versionCode into upper half of the long to ensure it doesn't somehow
+                // exactly offset an increase in time.
+                return pi.lastUpdateTime ^ (((long) pi.versionCode) << 32);
             } catch (PackageManager.NameNotFoundException e) {
                 throw new RuntimeException(e);
             }