Add DidNavigateMainFrame to the TabObserver.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/TabObserver.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/TabObserver.java b/chrome/android/java/src/org/chromium/chrome/browser/TabObserver.java
index f7a0faf3dbef4f8433437d13739e1d5f77140d4b..cf95aa4ffba481de7ba5ffa751b756ccd7c97b75 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/TabObserver.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/TabObserver.java
@@ -163,6 +163,21 @@ public interface TabObserver {
             Tab tab, long frameId, boolean isMainFrame, String url, int transitionType);
 
     /**
+     * Called when the main frame of the page has committed.
+     *
+     * @param tab                         The notifying {@link Tab}.
+     * @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 isFragmentNavigation        Whether the main frame navigation did not cause changes
+     *                                    to the document (for example scrolling to a named anchor
+     *                                    or PopState).
+     * @param statusCode                  The HTTP status code of the navigation.
+     */
+    public void onDidNavigateMainFrame(Tab tab, String url, String baseUrl,
+            boolean isNavigationToDifferentPage, boolean isFragmentNavigation, int statusCode);
+
+    /**
      * Called when the theme color is changed
      * @param color the new color in ARGB format.
      */