Reland: Ntp: restore scroll position.

content/public/android/java/src/org/chromium/content_public/browser/NavigationController.java

Index: content/public/android/java/src/org/chromium/content_public/browser/NavigationController.java
diff --git a/content/public/android/java/src/org/chromium/content_public/browser/NavigationController.java b/content/public/android/java/src/org/chromium/content_public/browser/NavigationController.java
index 65da9eb17c6ea5383954a9e03a6df6edea2b1376..84b563713d695ea18b8a1a9af6a0ca6e3e7c483c 100644
--- a/content/public/android/java/src/org/chromium/content_public/browser/NavigationController.java
+++ b/content/public/android/java/src/org/chromium/content_public/browser/NavigationController.java
@@ -196,4 +196,20 @@ public interface NavigationController {
      * @param replaceEntry Whether to replace the current entry in source
      */
     public void copyStateFromAndPrune(NavigationController source, boolean replaceEntry);
+
+    /**
+     * Gets extra data on the {@link NavigationEntry} at {@code index}.
+     * @param index The index of the navigation entry.
+     * @param key The data key.
+     * @return The data value, or null if not found.
+     */
+    String getEntryExtraData(int index, String key);
+
+    /**
+     * Sets extra data on the {@link NavigationEntry} at {@code index}.
+     * @param index The index of the navigation entry.
+     * @param key The data key.
+     * @param value The data value.
+     */
+    void setEntryExtraData(int index, String key, String value);
 }