Support fullscreen api for chrome shell

chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java

Index: chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java
diff --git a/chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java b/chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java
index b64767bf3384e418c8bf96bbe49be9b167ad9c7d..b2c31ce1d6b1821ba9b5695a8feaacccb7d8d170 100644
--- a/chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java
+++ b/chrome/android/shell/java/src/org/chromium/chrome/shell/TabManager.java
@@ -112,6 +112,12 @@ public class TabManager extends LinearLayout {
             }
         };
         ChromeShellTab tab = new ChromeShellTab(getContext(), url, mWindow, client);
+        tab.addObserver(new EmptyTabObserver() {
+            @Override
+            public void onToggleFullscreenMode(Tab tab, boolean enable) {
+                 mToolbar.setVisibility(enable ? GONE : VISIBLE);
+            }
+        });
         setCurrentTab(tab);
     }