[Merge] Show Incognito tab switcher button on startup

chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java b/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java
index c37a9d9038f19797b2c9cd91ff04a47924fb9d5c..7885266fb69d53ff38365068d525d1de6b98da51 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/LayoutManager.java
@@ -7,6 +7,7 @@ package org.chromium.chrome.browser.compositor.layouts;
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.graphics.RectF;
+import android.os.Handler;
 import android.os.SystemClock;
 import android.view.MotionEvent;
 import android.view.View;
@@ -30,6 +31,7 @@ import org.chromium.chrome.browser.contextualsearch.ContextualSearchManagementDe
 import org.chromium.chrome.browser.dom_distiller.ReaderModeManagerDelegate;
 import org.chromium.chrome.browser.fullscreen.ChromeFullscreenManager;
 import org.chromium.chrome.browser.fullscreen.FullscreenManager;
+import org.chromium.chrome.browser.tabmodel.EmptyTabModelSelectorObserver;
 import org.chromium.chrome.browser.tabmodel.TabCreatorManager;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.content.browser.SPenSupport;
@@ -245,6 +247,8 @@ public abstract class LayoutManager implements LayoutUpdateHost, LayoutProvider,
         mContentContainer = androidContentContainer;
 
         if (mNextActiveLayout != null) startShowing(mNextActiveLayout, true);
+
+        updateLayoutForTabModelSelector();
     }
 
     /**
@@ -525,4 +529,30 @@ public abstract class LayoutManager implements LayoutUpdateHost, LayoutProvider,
             return Orientation.PORTRAIT;
         }
     }
+
+    /**
+     * Updates the Layout for the state of the {@link TabModelSelector} after initialization.
+     * If the TabModelSelector is not yet initialized when this function is called, a
+     * {@link TabModelSelectorObserver} is created to listen for when it is ready.
+     */
+    private void updateLayoutForTabModelSelector() {
+        if (mTabModelSelector.isTabStateInitialized() && getActiveLayout() != null) {
+            getActiveLayout().onTabStateInitialized();
+        } else {
+            mTabModelSelector.addObserver(new EmptyTabModelSelectorObserver() {
+                @Override
+                public void onTabStateInitialized() {
+                    if (getActiveLayout() != null) getActiveLayout().onTabStateInitialized();
+
+                    final EmptyTabModelSelectorObserver observer = this;
+                    new Handler().post(new Runnable() {
+                        @Override
+                        public void run() {
+                            mTabModelSelector.removeObserver(observer);
+                        }
+                    });
+                }
+            });
+        }
+    }
 }