Stop unfreezing tabs "frozen" for lazy loads

chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
index 74e7227d2c326444c29823ab977cf43307652365..5b5ce862b2b321658f72cd6c0ef104532cb7acb8 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
@@ -1144,13 +1144,23 @@ public class ChromeTabbedActivity extends ChromeActivity implements OverviewMode
     @Override
     public void onDestroyInternal() {
         if (mLayoutManager != null) mLayoutManager.removeOverviewModeObserver(this);
-        if (mTabModelSelectorTabObserver != null) mTabModelSelectorTabObserver.destroy();
+
+        if (mTabModelSelectorTabObserver != null) {
+            mTabModelSelectorTabObserver.destroy();
+            mTabModelSelectorTabObserver = null;
+        }
+
         if (mTabModelObserver != null) {
             for (TabModel model : mTabModelSelectorImpl.getModels()) {
                 model.removeObserver(mTabModelObserver);
             }
         }
-        if (mUndoBarPopupController != null) mUndoBarPopupController.destroy();
+
+        if (mUndoBarPopupController != null) {
+            mUndoBarPopupController.destroy();
+            mUndoBarPopupController = null;
+        }
+
         super.onDestroyInternal();
     }