Support fullscreen api for chrome shell

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

Index: chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellTab.java
diff --git a/chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellTab.java b/chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellTab.java
index 04e857b2c4e445770a9919a17337e19137782a9b..1293564c4f3b0dce40788c74d3f36ddabc3d7606 100644
--- a/chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellTab.java
+++ b/chrome/android/shell/java/src/org/chromium/chrome/shell/ChromeShellTab.java
@@ -26,6 +26,7 @@ import org.chromium.ui.base.WindowAndroid;
 public class ChromeShellTab extends Tab {
     // Tab state
     private boolean mIsLoading;
+    private boolean mIsFullscreen = false;
 
     /**
      * @param context           The Context the view is running in.
@@ -122,5 +123,16 @@ public class ChromeShellTab extends Tab {
         public void onLoadStopped() {
             mIsLoading = false;
         }
+
+        @Override
+        public void toggleFullscreenModeForTab(boolean enterFullscreen) {
+            mIsFullscreen = enterFullscreen;
+            super.toggleFullscreenModeForTab(enterFullscreen);
+        }
+
+        @Override
+        public boolean isFullscreenForTabOrPending() {
+            return mIsFullscreen;
+        }
     }
 }