Add methods to SceneOverlay interface

chrome/android/java/src/org/chromium/chrome/browser/compositor/overlays/SceneOverlay.java

Index: chrome/android/java/src/org/chromium/chrome/browser/compositor/overlays/SceneOverlay.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/compositor/overlays/SceneOverlay.java b/chrome/android/java/src/org/chromium/chrome/browser/compositor/overlays/SceneOverlay.java
index 79648802cf39e3ce21e86fac0eca4c0100e4fb75..be165a9d4c766f485f75c709ca3aa49ed2d6f517 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/compositor/overlays/SceneOverlay.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/compositor/overlays/SceneOverlay.java
@@ -62,6 +62,22 @@ public interface SceneOverlay {
     boolean updateOverlay(long time, long dt);
 
     /**
+     * Notification that the system back button was pressed.
+     * @return True if system back button press was consumed by this overlay.
+     */
+    boolean onBackPressed();
+
+    /**
+     * A notification to the overlay that the containing layout is being hidden.
+     */
+    void onHideLayout();
+
+    /**
+     * @return True if this overlay handles tab creation.
+     */
+    boolean handlesTabCreating();
+
+    /**
      * Notify the a title has changed.
      *
      * @param tabId     The id of the tab that has changed.