DCHECK that jstring to C++ string conversions don't pass in null.

chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java

 // Copyright 2014 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.chrome.browser.tab;
 
 import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
 import android.content.res.Resources;
@@ skipping 657 matching lines @@
     private void restoreFieldsFromState(TabState state) {
         assert state != null;
         mAppAssociatedWith = state.openerAppId;
         mFrozenContentsState = state.contentsState;
         mSyncId = (int) state.syncId;
         mShouldPreserve = state.shouldPreserve;
         mTimestampMillis = state.timestampMillis;
         mUrl = state.getVirtualUrlFromState();
 
         mTitle = state.getDisplayTitleFromState();
-        mIsTitleDirectionRtl = LocalizationUtils.getFirstStrongCharacterDirection(mTitle)
-                == LocalizationUtils.RIGHT_TO_LEFT;
+        mIsTitleDirectionRtl = mTitle != null
+                && LocalizationUtils.getFirstStrongCharacterDirection(mTitle)
+                        == LocalizationUtils.RIGHT_TO_LEFT;
     }
 
     /**
      * Adds a {@link TabObserver} to be notified on {@link Tab} changes.
      * @param observer The {@link TabObserver} to add.
      */
     public void addObserver(TabObserver observer) {
         mObservers.addObserver(observer);
     }
 
@@ skipping 2375 matching lines @@
     private native void nativeSetInterceptNavigationDelegate(long nativeTabAndroid,
             InterceptNavigationDelegate delegate);
     private native void nativeAttachToTabContentManager(long nativeTabAndroid,
             TabContentManager tabContentManager);
     private native void nativeAttachOverlayContentViewCore(long nativeTabAndroid,
             ContentViewCore content, boolean visible);
     private native void nativeDetachOverlayContentViewCore(long nativeTabAndroid,
             ContentViewCore content);
     private native boolean nativeHasPrerenderedUrl(long nativeTabAndroid, String url);
 }