Tab manager view should hide on press of back key

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 8dc755b2df7914bd080ca3e9a375b64e5138cc78..272b91d80b0bb6026b123b798752a9d3cab51067 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
@@ -190,6 +190,14 @@ public class TabManager extends LinearLayout {
         mTabModelSelector.toggleTabSwitcher();
     }
 
+    public boolean isTabSwitcherVisible() {
+        return mTabModelSelector.isTabSwitcherVisible();
+    }
+
+    public void hideTabSwitcher() {
+        mTabModelSelector.hideTabSwitcher();
+    }
+
     /**
      * Opens a URL in the current tab if one exists, or in a new tab otherwise.
      * @param url The URL to open.