[Android] Fix toolbar jumping in after returning to Chrome.

chrome/android/java/src/org/chromium/chrome/browser/fullscreen/ChromeFullscreenManager.java

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.fullscreen;
 
 import android.app.Activity;
 import android.content.res.Resources;
 import android.view.Gravity;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewGroup.LayoutParams;
 import android.view.Window;
 import android.widget.FrameLayout;
 
 import org.chromium.base.ActivityState;
 import org.chromium.base.ApplicationStatus;
 import org.chromium.base.ApplicationStatus.ActivityStateListener;
 import org.chromium.base.BaseChromiumApplication;
 import org.chromium.base.BaseChromiumApplication.WindowFocusChangedListener;
+import org.chromium.base.ThreadUtils;
 import org.chromium.base.TraceEvent;
 import org.chromium.base.library_loader.LibraryLoader;
 import org.chromium.chrome.browser.fullscreen.FullscreenHtmlApiHandler.FullscreenHtmlApiDelegate;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tabmodel.TabModel.TabSelectionType;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.browser.tabmodel.TabModelSelectorTabModelObserver;
 import org.chromium.chrome.browser.util.ViewUtils;
 import org.chromium.chrome.browser.widget.ControlContainer;
 import org.chromium.content.browser.ContentVideoView;
 import org.chromium.content.browser.ContentViewCore;
 import org.chromium.content_public.common.BrowserControlsState;
 
 import java.util.ArrayList;
 
 /**
  * A class that manages control and content views to create the fullscreen mode.
  */
 public class ChromeFullscreenManager
         extends FullscreenManager implements ActivityStateListener, WindowFocusChangedListener {
 
+    // The amount of time to delay the control show request after returning to a once visible
+    // activity.  This delay is meant to allow Android to run its Activity focusing animation and
+    // have the controls scroll back in smoothly once that has finished.
+    private static final long ACTIVITY_RETURN_SHOW_REQUEST_DELAY_MS = 100;
+
     private final Activity mActivity;
     private final Window mWindow;
     private final BrowserStateBrowserControlsVisibilityDelegate mBrowserVisibilityDelegate;
     private final boolean mIsBottomControls;
 
     private ControlContainer mControlContainer;
     private int mTopControlContainerHeight;
     private int mBottomControlContainerHeight;
     private TabModelSelector mTabModelSelector;
     private TabModelSelectorTabModelObserver mTabModelObserver;
@@ skipping 129 matching lines @@
     /**
      * @return The visibility delegate that allows browser UI to control the browser control
      *         visibility.
      */
     public BrowserStateBrowserControlsVisibilityDelegate getBrowserVisibilityDelegate() {
         return mBrowserVisibilityDelegate;
     }
 
     @Override
     public void setTab(Tab tab) {
+        Tab previousTab = getTab();
         super.setTab(tab);
         mBrowserVisibilityDelegate.setTab(getTab());
-        if (tab != null) mBrowserVisibilityDelegate.showControlsTransient();
+        if (tab != null && previousTab != getTab()) {
+            mBrowserVisibilityDelegate.showControlsTransient();
+        }
     }
 
     @Override
     public void onActivityStateChange(Activity activity, int newState) {
         if (newState == ActivityState.STOPPED) {
             // Exit fullscreen in onStop to ensure the system UI flags are set correctly when
             // showing again (on JB MR2+ builds, the omnibox would be covered by the
             // notification bar when this was done in onStart()).
             setPersistentFullscreenMode(false);
         } else if (newState == ActivityState.STARTED) {
-            mBrowserVisibilityDelegate.showControlsTransient();
+            ThreadUtils.postOnUiThreadDelayed(new Runnable() {
+                @Override
+                public void run() {
+                    mBrowserVisibilityDelegate.showControlsTransient();
+                }
+            }, ACTIVITY_RETURN_SHOW_REQUEST_DELAY_MS);
         } else if (newState == ActivityState.DESTROYED) {
             ApplicationStatus.unregisterActivityStateListener(this);
             ((BaseChromiumApplication) mWindow.getContext().getApplicationContext())
                     .unregisterWindowFocusChangedListener(this);
 
             mTabModelObserver.destroy();
         }
     }
 
     @Override
@@ skipping 410 matching lines @@
             updateVisuals();
         }
     }
 
     @Override
     public void onContentViewScrollingStateChanged(boolean scrolling) {
         mContentViewScrolling = scrolling;
         if (!scrolling) updateVisuals();
     }
 }