Trust the renderer's same-document navigation flag if it is a same-origin nav.

content/public/android/java/src/org/chromium/content/browser/WebContentsObserverAndroid.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.content.browser;
 
 import org.chromium.base.CalledByNative;
 import org.chromium.base.JNINamespace;
 
 /**
@@ skipping 37 matching lines @@
     @CalledByNative
     public void didFailLoad(boolean isProvisionalLoad,
             boolean isMainFrame, int errorCode, String description, String failingUrl) {
     }
 
     /**
      * Called when the main frame of the page has committed.
      * @param url The validated url for the page.
      * @param baseUrl The validated base url for the page.
      * @param isNavigationToDifferentPage Whether the main frame navigated to a different page.
-     * @param isNavigationInPage Whether the main frame navigation did not cause changes to the
-     *                           document (for example scrolling to a named anchor or PopState).
+     * @param isFragmentNavigation Whether the main frame navigation did not cause changes to the
+     *                             document (for example scrolling to a named anchor or PopState).
      */
     @CalledByNative
     public void didNavigateMainFrame(String url, String baseUrl,
-            boolean isNavigationToDifferentPage, boolean isNavigationInPage) {
+            boolean isNavigationToDifferentPage, boolean isFragmentNavigation) {
     }
 
     /**
      * Called when the page had painted something non-empty.
      */
     @CalledByNative
     public void didFirstVisuallyNonEmptyPaint() {
     }
 
     /**
@@ skipping 86 matching lines @@
     public void detachFromWebContents() {
         if (mNativeWebContentsObserverAndroid != 0) {
             nativeDestroy(mNativeWebContentsObserverAndroid);
             mNativeWebContentsObserverAndroid = 0;
         }
     }
 
     private native long nativeInit(long contentViewCorePtr);
     private native void nativeDestroy(long nativeWebContentsObserverAndroid);
 }