Remove Navigation Transitions from Chromium

chrome/android/java/src/org/chromium/chrome/browser/tab/TransitionPageHelper.java

Index: chrome/android/java/src/org/chromium/chrome/browser/tab/TransitionPageHelper.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tab/TransitionPageHelper.java b/chrome/android/java/src/org/chromium/chrome/browser/tab/TransitionPageHelper.java
deleted file mode 100644
index e97f8b50fe037c1f285e403d094166d0f3ef9196..0000000000000000000000000000000000000000
--- a/chrome/android/java/src/org/chromium/chrome/browser/tab/TransitionPageHelper.java
+++ /dev/null
@@ -1,951 +0,0 @@
-// Copyright 2015 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.tab;
-
-import android.animation.Animator;
-import android.animation.AnimatorListenerAdapter;
-import android.animation.ObjectAnimator;
-import android.annotation.TargetApi;
-import android.app.Activity;
-import android.app.ActivityOptions;
-import android.content.Context;
-import android.content.Intent;
-import android.graphics.Rect;
-import android.os.Build;
-import android.os.Handler;
-import android.util.Pair;
-import android.view.View;
-import android.widget.FrameLayout;
-
-import org.chromium.base.ActivityState;
-import org.chromium.base.ApplicationStatus;
-import org.chromium.base.ApplicationStatus.ActivityStateListener;
-import org.chromium.base.CalledByNative;
-import org.chromium.base.FieldTrialList;
-import org.chromium.chrome.browser.ContentViewUtil;
-import org.chromium.chrome.browser.EmptyTabObserver;
-import org.chromium.chrome.browser.Tab;
-import org.chromium.content.browser.ContentView;
-import org.chromium.content.browser.ContentViewClient;
-import org.chromium.content.browser.ContentViewCore;
-import org.chromium.content_public.browser.JavaScriptCallback;
-import org.chromium.content_public.browser.LoadUrlParams;
-import org.chromium.content_public.browser.NavigationTransitionDelegate;
-import org.chromium.content_public.browser.WebContentsObserver;
-import org.chromium.ui.base.WindowAndroid;
-
-import java.util.ArrayList;
-
-/**
- * Responsible for transition content view creation and management.
- */
-public class TransitionPageHelper extends EmptyTabObserver {
-    private static final String TRANSITION_URL = "about:blank";
-
-    private static final int TRANSITION_MS = 300;
-    private static final int TRANSITION_DEFAULT_TIMEOUT = 500;
-    private static final int TRANSITION_DEFAULT_FRAMES = 2;
-
-    // Transition state when the transition page is active.
-    private static final int STATE_NONE = 0;
-    private static final int STATE_TRANSITION_STARTING = 1;
-    private static final int STATE_WAIT_FOR_OUTGOING_UNLOADED = 2;
-    private static final int STATE_WAIT_FOR_INCOMING_DCL = 3;
-    private static final int STATE_UNLOAD_TRANSITION = 4;
-    private static final int STATE_WAIT_FOR_TRANSITION_UNLOAD = 5;
-    // Web to native app transition states
-    private static final int STATE_WAIT_FOR_FETCH_TRANSITION_ELEMENTS = 6;
-    private static final int STATE_WAIT_FOR_CURRENT_UNLOAD_TO_NATIVE_APP = 7;
-    private static final int STATE_WAIT_FOR_NAVIGATE_TO_NATIVE_APP = 8;
-    private static final int STATE_WAIT_FOR_BACK_FROM_NATIVE_APP = 9;
-
-    // The activity associated with the tab.
-    private final Activity mActivity;
-
-    // Native pointer corresponding to the current object.
-    private long mNativeTransitionPageHelperPtr;
-
-    // The webcontents observer on current content view of the transition page.
-    private WebContentsObserver mTransitionObserver;
-
-    // The webcontents observer on current content view of the tab.
-    private WebContentsObserver mSourceObserver;
-
-    // The context used to create content view.
-    private final Context mContext;
-
-    // Android window used to created content view.
-    private final WindowAndroid mWindowAndroid;
-
-    // The transition content view created to display over the tab.
-    private ContentViewCore mTransitionContentViewCore;
-
-    // The source content view being navigated.
-    private ContentViewCore mSourceContentViewCore;
-
-    // The tab associated with the background view.
-    private final Tab mTab;
-
-    // Set when the transition has had TRANSITION_MS ms to show.
-    private boolean mTransitionFinished;
-
-    // Set once the incoming page is ready to be shown, either because it's
-    // fired DOMContentLoaded, or timed out.
-    private boolean mDestinationReady;
-
-    // Set once the transition page has been painted.
-    private boolean mTransitionPainted;
-
-    // Incremented when the transition page is painted.
-    private int mTransitionFramesPainted;
-
-    // Set once the transition content view has fully loaded.
-    private boolean mTransitionLoaded;
-
-    // Set once the transition page has been unloaded (stylesheets have been applied
-    // and TRANSITION_MS ms have passed).
-    private boolean mTransitionUnloaded;
-
-    // Set once the incoming page has signalled that it's received bytes and has
-    // paused the navigation.
-    private boolean mDestinationReadyToResume;
-
-    // Set once the incoming page has been painted.
-    private boolean mDestinationPainted;
-
-    // Set once the incoming page has signaled DOMContentLoaded.
-    private boolean mDestinationDOMContentLoaded;
-
-    // Set once current page starts navigation transition to the native app.
-    private boolean mTransitionToNativeApp;
-
-    // Set once current page has been unloaded (exit transitions have been applied and
-    // TRANSITION_MS ms have passed).
-    private boolean mCurrentUnloadedToNativeApp;
-
-    // Set once current page has finished navigation to the native app.
-    private boolean mNavigateToNativeAppFinished;
-
-    // Set once current page is back from the native app.
-    private boolean mBackFromNativeApp;
-
-    // The id of the main frame of the navigating page.
-    private long mDestinationMainFrameID;
-
-    // An array of stylesheet URL's to apply to the transition page.
-    private final ArrayList<String> mTransitionStylesheets;
-
-    // The background colour of the incoming app.
-    private String mTransitionColor;
-
-    // The CSS selector that selects the transition elements of the source page.
-    private String mCSSSelector;
-
-    // The background of the outgoing app.
-    private String mSourceColor;
-
-    // The current state of the transition.
-    private int mState;
-
-    // The current visibility state of the transition page.
-    private boolean mVisible;
-
-    // The current opacity of the transition page.
-    private float mOpacity;
-
-    // Used to animate the opacity when fading the transition page.
-    private final ObjectAnimator mAnimator;
-
-    private final Handler mHandler;
-
-    // The Intent URL used during web to native app navigation transitions.
-    private String mIntentUrl;
-
-    // The Intent used during web to native app navigation transitions.
-    private Intent mIntent;
-
-    // The offset of the visible content.
-    private int mVisibleContentOffset;
-
-    // The transition elements.
-    private ArrayList<TransitionElement> mTransitionElements;
-
-    // The Views for the transition elements.
-    private ArrayList<TransitionElementView> mTransitionElementViews;
-
-    // Set once the transition elements are fetched.
-    private boolean mTransitionElementsFetched;
-
-    // Used to check if the transition elements are visible.
-    private boolean mTransitionElementVisible;
-
-    private ActivityStateListener mActivityStateListener = new ActivityStateListener() {
-        @Override
-        public void onActivityStateChange(Activity activity, int newState) {
-            assert activity == mActivity;
-
-            if (newState == ActivityState.RESUMED) {
-                backFromNativeAppOnResume();
-            } else if (newState == ActivityState.STARTED) {
-                backFromNativeAppOnStart();
-            }
-        }
-    };
-
-    private static class TransitionElement {
-        // Transition element's name.
-        private final String mName;
-
-        // Transition element's position and size.
-        private final Rect mRect;
-
-        public TransitionElement(String name, Rect rect) {
-            mName = name;
-            mRect = rect;
-        }
-
-        public String name() {
-            return mName;
-        }
-
-        public Rect rect() {
-            return mRect;
-        }
-    }
-
-    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
-    private class TransitionElementView extends View {
-        public TransitionElementView(Context context) {
-            super(context);
-        }
-
-        @Override
-        public void setAlpha(float alpha) {
-            if (mCSSSelector != null) {
-                if (!mTransitionElementVisible && Float.compare(alpha, 0) != 0) {
-                    mTransitionElementVisible = true;
-                    mSourceContentViewCore.getWebContents().showTransitionElements(mCSSSelector);
-
-                    // This is a hack. May only work on Android 5.0.
-                    // Delay 150ms. We need to wait for the CSS opacity property to take effect
-                    // before hiding the view. Thread.sleep(150ms) does not work because it pauses
-                    // the whole UI thread, including the CSS opacity effect. In Android 5.0,
-                    // Activity Transitions uses 3 postOnAnimation()s to delay hiding the view for
-                    // double-buffering. So we can add more delays there and give the run loop
-                    // chances to push frames.
-                    // Reference - Android 5.0 Lollipop source code:
-                    // frameworks/base/core/java/android/app/EnterTransitionCoordinator.java
-                    // - startSharedElementTransition()
-                    postOnAnimation(new Runnable() {
-                        static final int MIN_ANIMATION_FRAMES = 3;
-                        int mIterations = 0;
-                        @Override
-                        public void run() {
-                            try {
-                                Thread.sleep(50);
-                            } catch (InterruptedException e) {
-                                // Ignore
-                            }
-                            mIterations++;
-                            if (mIterations < MIN_ANIMATION_FRAMES) {
-                                postOnAnimation(this);
-                            }
-                        }
-                    });
-                } else if (mTransitionElementVisible && Float.compare(alpha, 0) == 0) {
-                    mTransitionElementVisible = false;
-                    mSourceContentViewCore.getWebContents().hideTransitionElements(mCSSSelector);
-                }
-            }
-            super.setAlpha(alpha);
-        }
-    }
-
-    /**
-     * Creates an instance of TransitionPageHelper.
-     * @param activity An instance of a {@link Activity}.
-     * @param windowAndroid An instance of a {@link WindowAndroid}.
-     * @param tab The {@link Tab} associated with current background view.
-     */
-    public TransitionPageHelper(Activity activity, WindowAndroid windowAndroid, Tab tab) {
-        mActivity = activity;
-        mContext = activity.getApplicationContext();
-        mWindowAndroid = windowAndroid;
-        mTab = tab;
-        mTab.addObserver(this);
-
-        mNativeTransitionPageHelperPtr = nativeInit();
-        mHandler = new Handler();
-        mTransitionStylesheets = new ArrayList<String>();
-        mTransitionElements = new ArrayList<TransitionElement>();
-        mTransitionElementViews = new ArrayList<TransitionElementView>();
-        mTransitionElementVisible = true;
-        mAnimator = ObjectAnimator.ofFloat(this, "transitionOpacity", 1.0f, 0.0f);
-        mAnimator.setDuration(TRANSITION_MS);
-        mAnimator.addListener(new AnimatorListenerAdapter() {
-            @Override
-            public void onAnimationEnd(Animator animation) {
-                if (mTransitionContentViewCore != null) {
-                    mTransitionContentViewCore.onHide();
-                }
-                mTransitionUnloaded = true;
-                updateState();
-            }
-        });
-        ApplicationStatus.registerStateListenerForActivity(mActivityStateListener, mActivity);
-
-        // Access the field trial so that it gets saved.
-        FieldTrialList.findFullName("NavigationTransitions");
-
-        resetTransitionState();
-    }
-
-    /**
-     * @return The {@link ContentViewCore} associated with the transition page.
-     */
-    public ContentViewCore getTransitionContentViewCore() {
-        return mTransitionContentViewCore;
-    }
-
-    /**
-     * Destroys the content view and the corresponding native object.
-     */
-    private void destroy() {
-        if (mNativeTransitionPageHelperPtr == 0) return;
-
-        ApplicationStatus.unregisterActivityStateListener(mActivityStateListener);
-
-        teardownNavigation();
-
-        if (mSourceObserver != null) {
-            mSourceObserver.destroy();
-            mSourceObserver = null;
-        }
-
-        nativeDestroy(mNativeTransitionPageHelperPtr);
-        mNativeTransitionPageHelperPtr = 0;
-    }
-
-    /**
-     * @return True iff a navigation transition is currently underway.
-     */
-    public boolean isTransitionRunning() {
-        return mState != STATE_NONE;
-    }
-
-    /**
-     * Schedules a default timeout to signal if we haven't seen enough frames painted.
-     */
-    private void scheduleTransitionFramesTimeout() {
-        mHandler.postDelayed(new Runnable() {
-            @Override
-            public void run() {
-                mTransitionFramesPainted = TRANSITION_DEFAULT_FRAMES;
-                updateState();
-            }
-        }, TRANSITION_DEFAULT_TIMEOUT);
-    }
-
-    /**
-     * Notifies the outgoing page that the transition elements have been shown,
-     * and posts a task to wait TRANSITION_MS ms for it to run.
-     */
-    private void scheduleCurrentToUnload() {
-        mHandler.postDelayed(
-                new Runnable() {
-                    @Override
-                    public void run() {
-                        mTransitionFinished = true;
-                        mTransitionContentViewCore.getWebContents().insertCSS(String.format(
-                                "@-webkit-keyframes __transition_crossfade {"
-                                + "from {background: %s; }%n"
-                                + "to {background: %s; }}%n"
-                                + "-webkit-animation: __transition_crossfade %dms forwards;",
-                                mSourceColor, mTransitionColor, TRANSITION_MS));
-                        scheduleTransitionFramesTimeout();
-                        updateState();
-                    }
-                }, TRANSITION_MS);
-
-        setTransitionVisibility(true);
-        setTransitionOpacity(1.0f);
-
-        if (mTransitionContentViewCore != null && mSourceContentViewCore != null) {
-            // Notify the outgoing page that the transition elements have
-            // been shown in the transition page, so that they can be hidden
-            // in the outgoing page.
-            mSourceContentViewCore.getWebContents().beginExitTransition(mCSSSelector, false);
-        }
-
-        applyTransitionStylesheets();
-    }
-
-    /**
-     * Adds the transition stylesheets to the document.
-     */
-    private void applyTransitionStylesheets() {
-        for (int i = 0; i < mTransitionStylesheets.size(); i++) {
-            mTransitionContentViewCore.getWebContents().addStyleSheetByURL(
-                    mTransitionStylesheets.get(i));
-        }
-    }
-
-    /**
-     * Smoothly fades out the transition page to cover up any per-pixel
-     * imperfections.
-     */
-    private void fadeOutTransition() {
-        mAnimator.start();
-    }
-
-    /**
-     * Handles the current state of the transition state machine. The state
-     * machine has two routes. The first one is web-to-web transition and the
-     * second one is web-to-native-app transition. Both routes start with
-     * STATE_TRANSITION_STARTING.
-     */
-    private void updateState() {
-        // Web to web transition state machine
-        if (mState == STATE_TRANSITION_STARTING) {
-            // Transition page hasn't been shown yet. If it's ready to go, show
-            // it and we can move on to waiting 300 ms for outgoing page to
-            // unload.
-            if (mTransitionPainted && mTransitionLoaded) {
-                scheduleCurrentToUnload();
-                mState = STATE_WAIT_FOR_OUTGOING_UNLOADED;
-            }
-        } else if (mState == STATE_WAIT_FOR_OUTGOING_UNLOADED) {
-            // Outgoing page gets 300 ms to unload. Once that's done, we can
-            // resume navigation, assuming the incoming page is ready to
-            // to navigate.
-            if (mDestinationReadyToResume && mTransitionFinished
-                    && mTransitionFramesPainted >= TRANSITION_DEFAULT_FRAMES) {
-                if (mSourceContentViewCore != null) {
-                    mSourceContentViewCore.getWebContents().resumeResponseDeferredAtStart();
-                }
-                mState = STATE_WAIT_FOR_INCOMING_DCL;
-                updateState();
-            }
-        } else if (mState == STATE_WAIT_FOR_INCOMING_DCL) {
-            // Once the navigation is resumed, we wait until we get the
-            // DOMContentLoaded signal from the incoming page before starting
-            // to unload the transition page.
-            if (mDestinationReady) {
-                mState = STATE_UNLOAD_TRANSITION;
-                updateState();
-            }
-        } else if (mState == STATE_UNLOAD_TRANSITION) {
-            // Once the transition page is unloaded, need to give it 300 ms
-            // to fade out to hide any per-pixel positioning differences.
-            fadeOutTransition();
-            mState = STATE_WAIT_FOR_TRANSITION_UNLOAD;
-        } else if (mState == STATE_WAIT_FOR_TRANSITION_UNLOAD) {
-            // Wait until the fade is done and tear down the transition page.
-            if (mTransitionUnloaded) {
-                teardownNavigation();
-                mState = STATE_NONE;
-            }
-        }
-
-        // Web to native app transition state machine
-        if (mState == STATE_TRANSITION_STARTING) {
-            if (mTransitionToNativeApp) {
-                mState = STATE_WAIT_FOR_FETCH_TRANSITION_ELEMENTS;
-                fetchTransitionElements();
-            }
-        } else if (mState == STATE_WAIT_FOR_FETCH_TRANSITION_ELEMENTS) {
-            if (mTransitionElementsFetched) {
-                mState = STATE_WAIT_FOR_CURRENT_UNLOAD_TO_NATIVE_APP;
-                scheduleCurrentToUnloadToNativeApp();
-            }
-        } else if (mState == STATE_WAIT_FOR_CURRENT_UNLOAD_TO_NATIVE_APP) {
-            if (mCurrentUnloadedToNativeApp) {
-                mState = STATE_WAIT_FOR_NAVIGATE_TO_NATIVE_APP;
-                navigateToNativeApp();
-            }
-        } else if (mState == STATE_WAIT_FOR_NAVIGATE_TO_NATIVE_APP) {
-            if (mNavigateToNativeAppFinished) {
-                mState = STATE_WAIT_FOR_BACK_FROM_NATIVE_APP;
-            }
-        } else if (mState == STATE_WAIT_FOR_BACK_FROM_NATIVE_APP) {
-            if (mBackFromNativeApp) {
-                cleanUpBackFromNativeApp();
-                teardownNavigation();
-                mState = STATE_NONE;
-            }
-        }
-    }
-
-    /**
-     * Notifies any listeners of opacity changes.
-     */
-    private void setTransitionOpacity(float opacity) {
-        mOpacity = opacity;
-
-        nativeSetOpacity(mNativeTransitionPageHelperPtr, mTransitionContentViewCore, opacity);
-    }
-
-    /**
-     * Notifies any listeners of visibility changes.
-     */
-    private void setTransitionVisibility(boolean visible) {
-        mVisible = visible;
-
-        if (mTransitionContentViewCore != null) mTransitionContentViewCore.setDrawsContent(visible);
-    }
-
-    /**
-     * @return The visibility state of the transition page.
-     */
-    public boolean isTransitionVisible() {
-        return mVisible;
-    }
-
-    /**
-     * @return The opacity of the transition page.
-     */
-    public float getTransitionOpacity() {
-        return mOpacity;
-    }
-
-    /**
-     * Called when a transition navigation is initiated to reset values to their defaults.
-     */
-    private void resetTransitionState() {
-        mTransitionUnloaded = false;
-        mTransitionFinished = false;
-        mDestinationReady = false;
-        mDestinationReadyToResume = false;
-        mDestinationPainted = false;
-        mDestinationDOMContentLoaded = false;
-        mDestinationMainFrameID = -1;
-        mTransitionPainted = false;
-        mTransitionFramesPainted = 0;
-        mTransitionLoaded = false;
-        mState = STATE_NONE;
-        mVisible = false;
-        mOpacity = 0.0f;
-        mTransitionStylesheets.clear();
-        mTransitionColor = null;
-        mCSSSelector = null;
-        mAnimator.cancel();
-        mTransitionElements.clear();
-        mTransitionElementsFetched = false;
-        removeTransitionElementViewsFromLayout();
-        mTransitionElementVisible = true;
-        mTransitionToNativeApp = false;
-        mCurrentUnloadedToNativeApp = false;
-        mNavigateToNativeAppFinished = false;
-        mBackFromNativeApp = false;
-        mIntentUrl = null;
-        mIntent = null;
-        if (mSourceContentViewCore != null) {
-            mVisibleContentOffset = mSourceContentViewCore.getViewportSizeOffsetHeightPix();
-        }
-    }
-
-    /**
-     * Called when a transition navigation is initiated. Creates a new transition
-     * content view and resets the state machine.
-     */
-    private void startTransitionNavigation() {
-        if (mState != STATE_NONE) return;
-
-        teardownNavigation();
-        resetTransitionState();
-
-        mState = STATE_TRANSITION_STARTING;
-
-        buildContentView();
-
-        // Grab the background color from the outgoing page, so we can add it
-        // to the transition layer.
-        JavaScriptCallback jsCallback = new JavaScriptCallback() {
-            @Override
-            public void handleJavaScriptResult(String jsonResult) {
-                mSourceColor = jsonResult.replaceAll("\"", "");
-            }
-        };
-
-        String script = "getComputedStyle(document.body).backgroundColor";
-        mSourceContentViewCore.getWebContents().evaluateJavaScript(script, jsCallback);
-    }
-
-    /**
-     * Detaches any observers and destroys the transition content view.
-     */
-    private void teardownNavigation() {
-        mHandler.removeCallbacksAndMessages(null);
-        if (mNativeTransitionPageHelperPtr == 0) return;
-
-        if (mTransitionObserver != null) {
-            mTransitionObserver.destroy();
-            mTransitionObserver = null;
-        }
-        if (mTransitionContentViewCore != null) {
-            if (mTab != null) mTab.detachOverlayContentViewCore(mTransitionContentViewCore);
-            mTransitionContentViewCore.destroy();
-            mTransitionContentViewCore = null;
-            nativeReleaseWebContents(mNativeTransitionPageHelperPtr);
-        }
-        mState = STATE_NONE;
-    }
-
-    /**
-     * Creates a new transition content view and notifies listeners.
-     */
-    private void buildContentView() {
-        if (mNativeTransitionPageHelperPtr == 0) return;
-
-        mTransitionContentViewCore = new ContentViewCore(mContext);
-        ContentView cv = new ContentView(mContext, mTransitionContentViewCore);
-        mTransitionContentViewCore.initialize(cv, cv,
-                ContentViewUtil.createWebContentsWithSharedSiteInstance(mSourceContentViewCore),
-                mWindowAndroid);
-
-        // The renderer should be set with the height considering the top controls(non-fullscreen
-        // mode).
-        mTransitionContentViewCore.setTopControlsHeight(
-                mTransitionContentViewCore.getTopControlsHeightPix(), true);
-
-        mTransitionObserver = createTransitionObserver();
-
-        if (mTab != null) mTab.attachOverlayContentViewCore(mTransitionContentViewCore, true, true);
-
-        nativeSetWebContents(mNativeTransitionPageHelperPtr, mTransitionContentViewCore);
-        setTransitionOpacity(0.0f);
-
-        mTransitionContentViewCore.setContentViewClient(new ContentViewClient() {
-            @Override
-            public void onOffsetsForFullscreenChanged(
-                    float topControlsOffsetYPix,
-                    float contentOffsetYPix,
-                    float overdrawBottomHeightPix) {
-                if (mState != STATE_WAIT_FOR_OUTGOING_UNLOADED) return;
-
-                if (mTransitionContentViewCore.getContentWidthCss()
-                        == mTab.getContentViewCore().getContentWidthCss()) {
-                    mTransitionFramesPainted++;
-                    updateState();
-                }
-            }
-        });
-    }
-
-    /**
-     * Creates an observer for the transition web contents, and listens specifically
-     * for paint and loading events.
-     */
-    private WebContentsObserver createTransitionObserver() {
-        return new WebContentsObserver(mTransitionContentViewCore.getWebContents()) {
-            @Override
-            public void didFirstVisuallyNonEmptyPaint() {
-                if (!mTransitionPainted) {
-                    mTransitionPainted = true;
-                    updateState();
-                }
-            }
-
-            @Override
-            public void didFinishLoad(long frameId, String validatedUrl, boolean isMainFrame) {
-                if (isMainFrame) {
-                    mTransitionLoaded = true;
-                    updateState();
-                }
-            }
-        };
-    }
-
-    /**
-     * Creates an observer for the tab's web contents, and listens specifically
-     * for transition, paint, and DOMContentLoaded events.
-     */
-    private WebContentsObserver createSourceObserver() {
-        return new WebContentsObserver(mSourceContentViewCore.getWebContents()) {
-            private void signalDestinationMaybeReady() {
-                if ((mDestinationDOMContentLoaded && mDestinationPainted) && !mDestinationReady) {
-                    mDestinationReady = true;
-                    updateState();
-                }
-            }
-
-            @Override
-            public void didFirstVisuallyNonEmptyPaint() {
-                mDestinationPainted = true;
-                signalDestinationMaybeReady();
-            }
-
-            @Override
-            public void documentLoadedInFrame(long frameId) {
-                if (frameId == mDestinationMainFrameID) {
-                    mDestinationDOMContentLoaded = true;
-                    signalDestinationMaybeReady();
-                    mHandler.postDelayed(
-                            new Runnable() {
-                                @Override
-                                public void run() {
-                                    mDestinationPainted = true;
-                                    signalDestinationMaybeReady();
-                                }
-                            }, TRANSITION_DEFAULT_TIMEOUT);
-                }
-            }
-
-            @Override
-            public void didFailLoad(boolean isProvisionalLoad,
-                    boolean isMainFrame, int errorCode, String description, String failingUrl) {
-                // Just consider a failed load as the destination is ready. The transition
-                // page will fade out naturally.
-                if (isMainFrame) {
-                    mDestinationReady = true;
-                    updateState();
-                }
-            }
-        };
-    }
-
-    @Override
-    public void onContentChanged(Tab tab) {
-        if (tab == mTab) {
-            if (mSourceContentViewCore != null && mSourceContentViewCore.getWebContents() != null) {
-                mSourceContentViewCore.getWebContents().setNavigationTransitionDelegate(null);
-            }
-
-            mSourceContentViewCore = tab.getContentViewCore();
-
-            if (mSourceObserver != null) {
-                mSourceObserver.destroy();
-                mSourceObserver = null;
-            }
-
-            if (mSourceContentViewCore == null) return;
-
-            mSourceObserver = createSourceObserver();
-            mSourceContentViewCore.getWebContents().setNavigationTransitionDelegate(
-                    new NavigationTransitionDelegate() {
-                        @Override
-                        public void didDeferAfterResponseStarted(String markup, String cssSelector,
-                                String color) {
-                            if (mTransitionContentViewCore != null && isTransitionRunning()) {
-                                mDestinationReadyToResume = true;
-
-                                LoadUrlParams navigationParams = new LoadUrlParams(TRANSITION_URL);
-
-                                mTransitionContentViewCore.getWebContents()
-                                        .getNavigationController().loadUrl(navigationParams);
-                                mTransitionContentViewCore.setBackgroundOpaque(false);
-                                mTransitionContentViewCore.getWebContents().setupTransitionView(
-                                        markup);
-                                mTransitionContentViewCore.onShow();
-
-                                setTransitionOpacity(0.0f);
-                                setTransitionVisibility(false);
-
-                                mTransitionColor = color;
-                                mCSSSelector = cssSelector;
-                            }
-                        }
-
-                        @Override
-                        public void didStartNavigationTransitionForFrame(long frameId) {
-                            startTransitionNavigation();
-                            mDestinationMainFrameID = frameId;
-                        }
-
-                        @Override
-                        public boolean willHandleDeferAfterResponseStarted() {
-                            return true;
-                        }
-
-                        @Override
-                        public void addEnteringStylesheetToTransition(String stylesheet) {
-                            if (mTransitionContentViewCore != null && isTransitionRunning()) {
-                                mTransitionStylesheets.add(stylesheet);
-                            }
-                        }
-
-                        @Override
-                        public void addNavigationTransitionElements(
-                                String name, int x, int y, int width, int height) {
-                            if (isTransitionRunning()) {
-                                Rect rect = new Rect(x, y, x + width, y + height);
-                                TransitionElement element = new TransitionElement(name, rect);
-                                mTransitionElements.add(element);
-                            }
-                        }
-
-                        @Override
-                        public void onTransitionElementsFetched(String cssSelector) {
-                            if (isTransitionRunning()) {
-                                mCSSSelector = cssSelector;
-                                mTransitionElementsFetched = true;
-                                updateState();
-                            }
-                        }
-                    });
-        }
-    }
-
-    @Override
-    public void onDestroyed(Tab tab) {
-        if (tab == mTab) {
-            destroy();
-        }
-    }
-
-    /**
-     * Check Whether transition is starting.
-     * @return Whether the transition is starting.
-     */
-    public boolean isTransitionStarting() {
-        return mState == STATE_TRANSITION_STARTING;
-    }
-
-    /**
-     * Transition to native app. This is the starting point of the web-to-native-app navigation
-     * transitions.
-     * @param url The Intent URL of the native app.
-     * @param intent The Intent of the native app.
-     */
-    public void transitionToNativeApp(String url, Intent intent) {
-        if (!isTransitionStarting()) return;
-        mIntentUrl = url;
-        mIntent = intent;
-        mTransitionToNativeApp = true;
-        updateState();
-    }
-
-    private void fetchTransitionElements() {
-        mSourceContentViewCore.getWebContents().fetchTransitionElements(mIntentUrl);
-    }
-
-    private void scheduleCurrentToUnloadToNativeApp() {
-        // Let the exit transition run for TRANSITION_MS.
-        mHandler.postDelayed(new Runnable() {
-                @Override
-                public void run() {
-                    mCurrentUnloadedToNativeApp = true;
-                    updateState();
-                }
-        }, TRANSITION_MS);
-
-        if (mSourceContentViewCore != null) {
-            mSourceContentViewCore.getWebContents().beginExitTransition(mCSSSelector, true);
-        }
-    }
-
-    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
-    private void navigateToNativeApp() {
-        FrameLayout rootContentView = (FrameLayout) mActivity.findViewById(android.R.id.content);
-        @SuppressWarnings("unchecked")
-        Pair<View, String>[] sharedElements = new Pair[mTransitionElements.size()];
-        for (int i = 0; i < mTransitionElements.size(); i++) {
-            // Create TransitionElementViews and add them to the root view
-            Rect r = mTransitionElements.get(i).rect();
-            int left = convertPagePxToDpi(r.left);
-            int top = convertPagePxToDpi(r.top) + mVisibleContentOffset;
-            int right = convertPagePxToDpi(r.right);
-            int bottom = convertPagePxToDpi(r.bottom) + mVisibleContentOffset;
-            FrameLayout.LayoutParams layoutParams =
-                    new FrameLayout.LayoutParams(right - left, bottom - top);
-            layoutParams.setMargins(left, top, right, bottom);
-
-            TransitionElementView v = new TransitionElementView(mActivity);
-            v.setId(View.generateViewId());
-            v.setTransitionName(mTransitionElements.get(i).name());
-            // Both setLayoutParams() and setLeft() etc are needed when setting the position and
-            // size.
-            v.setLayoutParams(layoutParams);
-            v.setLeft(left);
-            v.setTop(top);
-            v.setRight(right);
-            v.setBottom(bottom);
-
-            rootContentView.addView(v);
-            mTransitionElementViews.add(v);
-            sharedElements[i] = Pair.create((View) v, mTransitionElements.get(i).name());
-        }
-        ActivityOptions activityOptions =
-                ActivityOptions.makeSceneTransitionAnimation(mActivity, sharedElements);
-        // Remove FLAG_ACTIVITY_NEW_TASK.
-        int flags = mIntent.getFlags();
-        flags &= ~Intent.FLAG_ACTIVITY_NEW_TASK;
-        mIntent.setFlags(flags);
-        mActivity.startActivity(mIntent, activityOptions.toBundle());
-        transitionToNativeAppFinished();
-    }
-
-    /**
-     * The web page is now transitioned to the native app. Set the tab to be covered by the native
-     * app and update the state machine.
-     */
-    public void transitionToNativeAppFinished() {
-        if (mState != STATE_WAIT_FOR_NAVIGATE_TO_NATIVE_APP) return;
-        mNavigateToNativeAppFinished = true;
-        mTab.setCoveredByChildActivity(true);
-        updateState();
-    }
-
-    /**
-     * The web page is back from the native app when Chrome is in onStart() stage. Revert the exit
-     * transitions.
-     */
-    public void backFromNativeAppOnStart() {
-        if (mState != STATE_WAIT_FOR_BACK_FROM_NATIVE_APP) return;
-        if (mSourceContentViewCore != null) {
-            mSourceContentViewCore.getWebContents().revertExitTransition();
-        }
-    }
-
-    /**
-     * The web page is back from the native app when Chrome is in onResume() stage. Set the tab to
-     * be uncovered by the native app and update the state machine.
-     */
-    public void backFromNativeAppOnResume() {
-        if (mState != STATE_WAIT_FOR_BACK_FROM_NATIVE_APP) return;
-        mTab.setCoveredByChildActivity(false);
-        mBackFromNativeApp = true;
-        updateState();
-    }
-
-    private void cleanUpBackFromNativeApp() {
-        // Currently there is data left in TransitionRequestManager. We need to
-        // clear them to get correct future navigation behavior.
-        mSourceContentViewCore.getWebContents().clearNavigationTransitionData();
-        removeTransitionElementViewsFromLayout();
-    }
-
-    private void removeTransitionElementViewsFromLayout() {
-        // Remove the TransitionElementViews from the layout's view hierarchy.
-        FrameLayout rootContentView = (FrameLayout) mActivity.findViewById(android.R.id.content);
-        for (int i = 0; i < mTransitionElementViews.size(); i++) {
-            rootContentView.removeView(mTransitionElementViews.get(i));
-        }
-        mTransitionElementViews.clear();
-    }
-
-    /**
-     * Convert page pixels to dpis.
-     * @param pagePixel Page pixel value from the renderer.
-     * @return Page pixel in dpis.
-     */
-    private int convertPagePxToDpi(int pagePixel) {
-        float scale = mActivity.getResources().getDisplayMetrics().density;
-        return (int) Math.ceil(pagePixel * scale);
-    }
-
-    @CalledByNative
-    private long getNativePtr() {
-        return mNativeTransitionPageHelperPtr;
-    }
-
-    private native long nativeInit();
-    private native void nativeDestroy(long nativeTransitionPageHelper);
-    private native void nativeSetWebContents(long nativeTransitionPageHelper,
-            ContentViewCore contentViewCore);
-    private native void nativeReleaseWebContents(long nativeTransitionPageHelper);
-    private native void nativeSetOpacity(long nativeTransitionPageHelper,
-            ContentViewCore contentViewCore, float opacity);
-}