[Home] Move bottom sheet classes to widget/bottomsheet

chrome/android/java/src/org/chromium/chrome/browser/widget/BottomSheet.java

Index: chrome/android/java/src/org/chromium/chrome/browser/widget/BottomSheet.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/widget/BottomSheet.java b/chrome/android/java/src/org/chromium/chrome/browser/widget/BottomSheet.java
deleted file mode 100644
index c1f73b8fda59a5d8c8cceeabd0423e06777ed0f0..0000000000000000000000000000000000000000
--- a/chrome/android/java/src/org/chromium/chrome/browser/widget/BottomSheet.java
+++ /dev/null
@@ -1,836 +0,0 @@
-// Copyright 2017 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.widget;
-
-import android.animation.Animator;
-import android.animation.AnimatorListenerAdapter;
-import android.animation.ValueAnimator;
-import android.content.Context;
-import android.graphics.Region;
-import android.support.annotation.IntDef;
-import android.support.annotation.Nullable;
-import android.util.AttributeSet;
-import android.view.GestureDetector;
-import android.view.MotionEvent;
-import android.view.VelocityTracker;
-import android.view.View;
-import android.view.animation.DecelerateInterpolator;
-import android.view.animation.Interpolator;
-import android.widget.FrameLayout;
-
-import org.chromium.base.ApiCompatibilityUtils;
-import org.chromium.base.ObserverList;
-import org.chromium.base.VisibleForTesting;
-import org.chromium.chrome.R;
-import org.chromium.chrome.browser.NativePageHost;
-import org.chromium.chrome.browser.TabLoadStatus;
-import org.chromium.chrome.browser.fullscreen.ChromeFullscreenManager;
-import org.chromium.chrome.browser.ntp.NativePageFactory;
-import org.chromium.chrome.browser.tab.Tab;
-import org.chromium.chrome.browser.tabmodel.TabModel;
-import org.chromium.chrome.browser.tabmodel.TabModelSelector;
-import org.chromium.chrome.browser.util.MathUtils;
-import org.chromium.content_public.browser.LoadUrlParams;
-
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-
-/**
- * This class defines the bottom sheet that has multiple states and a persistently showing toolbar.
- * Namely, the states are:
- * - PEEK: Only the toolbar is visible at the bottom of the screen.
- * - HALF: The sheet is expanded to consume around half of the screen.
- * - FULL: The sheet is expanded to its full height.
- *
- * All the computation in this file is based off of the bottom of the screen instead of the top
- * for simplicity. This means that the bottom of the screen is 0 on the Y axis.
- */
-
-public class BottomSheet
-        extends FrameLayout implements FadingBackgroundView.FadingViewObserver, NativePageHost {
-    /** The different states that the bottom sheet can have. */
-    @IntDef({SHEET_STATE_PEEK, SHEET_STATE_HALF, SHEET_STATE_FULL})
-    @Retention(RetentionPolicy.SOURCE)
-    public @interface SheetState {}
-    public static final int SHEET_STATE_PEEK = 0;
-    public static final int SHEET_STATE_HALF = 1;
-    public static final int SHEET_STATE_FULL = 2;
-
-    /**
-     * The base duration of the settling animation of the sheet. 218 ms is a spec for material
-     * design (this is the minimum time a user is guaranteed to pay attention to something).
-     */
-    private static final long BASE_ANIMATION_DURATION_MS = 218;
-
-    /**
-     * The fraction of the way to the next state the sheet must be swiped to animate there when
-     * released. A smaller value here means a smaller swipe is needed to move the sheet around.
-     */
-    private static final float THRESHOLD_TO_NEXT_STATE = 0.5f;
-
-    /** The minimum y/x ratio that a scroll must have to be considered vertical. */
-    private static final float MIN_VERTICAL_SCROLL_SLOPE = 2.0f;
-
-    /**
-     * Information about the different scroll states of the sheet. Order is important for these,
-     * they go from smallest to largest.
-     */
-    private static final int[] sStates =
-            new int[] {SHEET_STATE_PEEK, SHEET_STATE_HALF, SHEET_STATE_FULL};
-    private final float[] mStateRatios = new float[] {0.0f, 0.55f, 0.95f};
-
-    /** The interpolator that the height animator uses. */
-    private final Interpolator mInterpolator = new DecelerateInterpolator(1.0f);
-
-    /** The list of observers of this sheet. */
-    private final ObserverList<BottomSheetObserver> mObservers = new ObserverList<>();
-
-    /** This is a cached array for getting the window location of different views. */
-    private final int[] mLocationArray = new int[2];
-
-    /** For detecting scroll and fling events on the bottom sheet. */
-    private GestureDetector mGestureDetector;
-
-    /** Whether or not the user is scrolling the bottom sheet. */
-    private boolean mIsScrolling;
-
-    /** Track the velocity of the user's scrolls to determine up or down direction. */
-    private VelocityTracker mVelocityTracker;
-
-    /** The animator used to move the sheet to a fixed state when released by the user. */
-    private ValueAnimator mSettleAnimator;
-
-    /** The height of the toolbar. */
-    private float mToolbarHeight;
-
-    /** The width of the view that contains the bottom sheet. */
-    private float mContainerWidth;
-
-    /** The height of the view that contains the bottom sheet. */
-    private float mContainerHeight;
-
-    /** The current sheet state. If the sheet is moving, this will be the target state. */
-    private int mCurrentState;
-
-    /** Used for getting the current tab. */
-    private TabModelSelector mTabModelSelector;
-
-    /** The fullscreen manager for information about toolbar offsets. */
-    private ChromeFullscreenManager mFullscreenManager;
-
-    /** A handle to the content being shown by the sheet. */
-    private BottomSheetContent mSheetContent;
-
-    /** A handle to the toolbar control container. */
-    private View mControlContainer;
-
-    /** A placeholder for if there is no content in the bottom sheet. */
-    private View mPlaceholder;
-
-    /** A handle to the FrameLayout that holds the content of the bottom sheet. */
-    private FrameLayout mBottomSheetContentContainer;
-
-    /**
-     * The last ratio sent to observers of onTransitionPeekToHalf(). This is used to ensure the
-     * final value sent to these observers is 1.0f.
-     */
-    private float mLastPeekToHalfRatioSent;
-
-    /** The FrameLayout used to hold the bottom sheet toolbar. */
-    private FrameLayout mToolbarHolder;
-
-    /**
-     * The default toolbar view. This is shown when the current bottom sheet content doesn't have
-     * its own toolbar and when the bottom sheet is closed.
-     */
-    private View mDefaultToolbarView;
-
-    /** The last non-default toolbar view that was attached to mToolbarHolder. */
-    private View mLastToolbarView;
-
-    /**
-     * An interface defining content that can be displayed inside of the bottom sheet for Chrome
-     * Home.
-     */
-    public interface BottomSheetContent {
-        /**
-         * Gets the {@link View} that holds the content to be displayed in the Chrome Home bottom
-         * sheet.
-         * @return The content view.
-         */
-        View getContentView();
-
-        /**
-         * Get the {@link View} that contains the toolbar specific to the content being displayed.
-         * If null is returned, the omnibox is used.
-         * TODO(mdjones): This still needs implementation in the sheet.
-         *
-         * @return The toolbar view.
-         */
-        @Nullable
-        View getToolbarView();
-
-        /**
-         * @return The vertical scroll offset of the content view.
-         */
-        int getVerticalScrollOffset();
-
-        /**
-         * Called to destroy the BottomSheetContent when it is no longer in use.
-         */
-        void destroy();
-    }
-
-    /**
-     * This class is responsible for detecting swipe and scroll events on the bottom sheet or
-     * ignoring them when appropriate.
-     */
-    private class BottomSheetSwipeDetector extends GestureDetector.SimpleOnGestureListener {
-        @Override
-        public boolean onDown(MotionEvent e) {
-            return true;
-        }
-
-        @Override
-        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
-                float distanceY) {
-            // Only start scrolling if the scroll is up or down. If the user is already scrolling,
-            // continue moving the sheet.
-            float slope = Math.abs(distanceX) > 0f ? Math.abs(distanceY) / Math.abs(distanceX) : 0f;
-            if (!mIsScrolling && slope < MIN_VERTICAL_SCROLL_SLOPE) {
-                mVelocityTracker.clear();
-                return false;
-            }
-
-            // Cancel the settling animation if it is running so it doesn't conflict with where the
-            // user wants to move the sheet.
-            cancelAnimation();
-
-            mVelocityTracker.addMovement(e2);
-
-            float currentShownRatio =
-                    mContainerHeight > 0 ? getSheetOffsetFromBottom() / mContainerHeight : 0;
-            boolean isSheetInMaxPosition =
-                    MathUtils.areFloatsEqual(currentShownRatio, getFullRatio());
-
-            // Allow the bottom sheet's content to be scrolled up without dragging the sheet down.
-            if (!isTouchEventInToolbar(e2) && isSheetInMaxPosition && mSheetContent != null
-                    && mSheetContent.getVerticalScrollOffset() > 0) {
-                mIsScrolling = false;
-                return false;
-            }
-
-            // If the sheet is in the max position, don't move the sheet if the scroll is upward.
-            // Instead, allow the sheet's content to handle it if it needs to.
-            if (isSheetInMaxPosition && distanceY > 0) {
-                mIsScrolling = false;
-                return false;
-            }
-
-            // Similarly, if the sheet is in the min position, don't move if the scroll is downward.
-            if (currentShownRatio <= getPeekRatio() && distanceY < 0) {
-                mIsScrolling = false;
-                return false;
-            }
-
-            float newOffset = getSheetOffsetFromBottom() + distanceY;
-            setSheetOffsetFromBottom(MathUtils.clamp(newOffset, getMinOffset(), getMaxOffset()));
-
-            mIsScrolling = true;
-            return true;
-        }
-
-        @Override
-        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
-                float velocityY) {
-            cancelAnimation();
-
-            // Figure out the projected state of the sheet and animate there. Note that a swipe up
-            // will have a negative velocity, swipe down will have a positive velocity. Negate this
-            // values so that the logic is more intuitive.
-            @SheetState
-            int targetState = getTargetSheetState(
-                    getSheetOffsetFromBottom() + getFlingDistance(-velocityY), -velocityY);
-            setSheetState(targetState, true);
-            mIsScrolling = false;
-
-            return true;
-        }
-    }
-
-    /**
-     * Constructor for inflation from XML.
-     * @param context An Android context.
-     * @param atts The XML attributes.
-     */
-    public BottomSheet(Context context, AttributeSet atts) {
-        super(context, atts);
-
-        mVelocityTracker = VelocityTracker.obtain();
-
-        mGestureDetector = new GestureDetector(context, new BottomSheetSwipeDetector());
-        mGestureDetector.setIsLongpressEnabled(false);
-    }
-
-    @Override
-    public boolean onInterceptTouchEvent(MotionEvent e) {
-        if (!canMoveSheet()) return false;
-
-        // The incoming motion event may have been adjusted by the view sending it down. Create a
-        // motion event with the raw (x, y) coordinates of the original so the gesture detector
-        // functions properly.
-        mGestureDetector.onTouchEvent(createRawMotionEvent(e));
-        return mIsScrolling;
-    }
-
-    @Override
-    public boolean onTouchEvent(MotionEvent e) {
-        if (isToolbarAndroidViewHidden()) return false;
-
-        // The down event is interpreted above in onInterceptTouchEvent, it does not need to be
-        // interpreted a second time.
-        if (e.getActionMasked() != MotionEvent.ACTION_DOWN) {
-            mGestureDetector.onTouchEvent(createRawMotionEvent(e));
-        }
-
-        // If the user is scrolling and the event is a cancel or up action, update scroll state
-        // and return.
-        if (e.getActionMasked() == MotionEvent.ACTION_UP
-                || e.getActionMasked() == MotionEvent.ACTION_CANCEL) {
-            mIsScrolling = false;
-
-            mVelocityTracker.computeCurrentVelocity(1000);
-
-            // If an animation was not created to settle the sheet at some state, do it now.
-            if (mSettleAnimator == null) {
-                // Negate velocity so a positive number indicates a swipe up.
-                float currentVelocity = -mVelocityTracker.getYVelocity();
-                @SheetState
-                int targetState = getTargetSheetState(getSheetOffsetFromBottom(), currentVelocity);
-
-                setSheetState(targetState, true);
-            }
-        }
-
-        return true;
-    }
-
-    @Override
-    public boolean gatherTransparentRegion(Region region) {
-        // TODO(mdjones): Figure out what this should actually be set to since the view animates
-        // without necessarily calling this method again.
-        region.setEmpty();
-        return true;
-    }
-
-    /**
-     * @param tabModelSelector A TabModelSelector for getting the current tab and activity.
-     */
-    public void setTabModelSelector(TabModelSelector tabModelSelector) {
-        mTabModelSelector = tabModelSelector;
-    }
-
-    /**
-     * @param fullscreenManager Chrome's fullscreen manager for information about toolbar offsets.
-     */
-    public void setFullscreenManager(ChromeFullscreenManager fullscreenManager) {
-        mFullscreenManager = fullscreenManager;
-    }
-
-    /**
-     * @return Whether or not the toolbar Android View is hidden due to being scrolled off-screen.
-     */
-    private boolean isToolbarAndroidViewHidden() {
-        return mFullscreenManager == null || mFullscreenManager.getBottomControlOffset() > 0
-                || mControlContainer.getVisibility() != VISIBLE;
-    }
-
-    /**
-     * Adds layout change listeners to the views that the bottom sheet depends on. Namely the
-     * heights of the root view and control container are important as they are used in many of the
-     * calculations in this class.
-     * @param root The container of the bottom sheet.
-     * @param controlContainer The container for the toolbar.
-     */
-    public void init(View root, View controlContainer) {
-        mControlContainer = controlContainer;
-        mToolbarHeight = mControlContainer.getHeight();
-
-        mBottomSheetContentContainer = (FrameLayout) findViewById(R.id.bottom_sheet_content);
-
-        mCurrentState = SHEET_STATE_PEEK;
-
-        // Listen to height changes on the root.
-        root.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
-            @Override
-            public void onLayoutChange(View v, int left, int top, int right, int bottom,
-                    int oldLeft, int oldTop, int oldRight, int oldBottom) {
-                // Make sure the size of the layout actually changed.
-                if (bottom - top == oldBottom - oldTop && right - left == oldRight - oldLeft) {
-                    return;
-                }
-
-                mContainerWidth = right - left;
-                mContainerHeight = bottom - top;
-                updateSheetDimensions();
-
-                cancelAnimation();
-                setSheetState(mCurrentState, false);
-            }
-        });
-
-        // Listen to height changes on the toolbar.
-        controlContainer.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
-            @Override
-            public void onLayoutChange(View v, int left, int top, int right, int bottom,
-                    int oldLeft, int oldTop, int oldRight, int oldBottom) {
-                // Make sure the size of the layout actually changed.
-                if (bottom - top == oldBottom - oldTop && right - left == oldRight - oldLeft) {
-                    return;
-                }
-
-                mToolbarHeight = bottom - top;
-                updateSheetDimensions();
-
-                cancelAnimation();
-                setSheetState(mCurrentState, false);
-            }
-        });
-
-        mPlaceholder = new View(getContext());
-        LayoutParams placeHolderParams =
-                new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
-        mPlaceholder.setBackgroundColor(
-                ApiCompatibilityUtils.getColor(getResources(), android.R.color.white));
-        mBottomSheetContentContainer.addView(mPlaceholder, placeHolderParams);
-
-        mToolbarHolder = (FrameLayout) mControlContainer.findViewById(R.id.toolbar_holder);
-        mDefaultToolbarView = mControlContainer.findViewById(R.id.toolbar);
-    }
-
-    @Override
-    public int loadUrl(LoadUrlParams params, boolean incognito) {
-        for (BottomSheetObserver o : mObservers) o.onLoadUrl(params.getUrl());
-
-        // Native page URLs in this context do not need to communicate with the tab.
-        if (NativePageFactory.isNativePageUrl(params.getUrl(), incognito)) {
-            return TabLoadStatus.PAGE_LOAD_FAILED;
-        }
-
-        // In all non-native cases, minimize the sheet.
-        setSheetState(SHEET_STATE_PEEK, true);
-
-        assert mTabModelSelector != null;
-
-        // First try to get the tab behind the sheet.
-        if (getActiveTab() != null && getActiveTab().isIncognito() == incognito) {
-            return getActiveTab().loadUrl(params);
-        }
-
-        // If no compatible tab is active behind the sheet, open a new one.
-        mTabModelSelector.openNewTab(
-                params, TabModel.TabLaunchType.FROM_CHROME_UI, getActiveTab(), incognito);
-        return TabLoadStatus.DEFAULT_PAGE_LOAD;
-    }
-
-    @Override
-    public boolean isIncognito() {
-        if (getActiveTab() == null) return false;
-        return getActiveTab().isIncognito();
-    }
-
-    @Override
-    public int getParentId() {
-        return Tab.INVALID_TAB_ID;
-    }
-
-    @Override
-    public Tab getActiveTab() {
-        return mTabModelSelector.getCurrentTab();
-    }
-
-    @Override
-    public boolean isVisible() {
-        return mCurrentState != SHEET_STATE_PEEK;
-    }
-
-    /**
-     * Gets the minimum offset of the bottom sheet.
-     * @return The min offset.
-     */
-    public float getMinOffset() {
-        return getPeekRatio() * mContainerHeight;
-    }
-
-    /**
-     * Gets the sheet's offset from the bottom of the screen.
-     * @return The sheet's distance from the bottom of the screen.
-     */
-    public float getSheetOffsetFromBottom() {
-        return mContainerHeight - getTranslationY();
-    }
-
-    /**
-     * Show content in the bottom sheet's content area.
-     * @param content The {@link BottomSheetContent} to show.
-     */
-    public void showContent(BottomSheetContent content) {
-        // If the desired content is already showing, do nothing.
-        if (mSheetContent == content) return;
-
-        if (mSheetContent != null) {
-            mBottomSheetContentContainer.removeView(mSheetContent.getContentView());
-            mSheetContent = null;
-        }
-
-        if (content == null) {
-            mBottomSheetContentContainer.addView(mPlaceholder);
-            return;
-        }
-
-        mBottomSheetContentContainer.removeView(mPlaceholder);
-        mSheetContent = content;
-        mBottomSheetContentContainer.addView(mSheetContent.getContentView());
-
-        if (mLastToolbarView != null) {
-            mToolbarHolder.removeView(mLastToolbarView);
-            mLastToolbarView = null;
-        }
-
-        if (mSheetContent.getToolbarView() != null) {
-            mLastToolbarView = mSheetContent.getToolbarView();
-            mToolbarHolder.addView(mSheetContent.getToolbarView());
-            mDefaultToolbarView.setVisibility(View.GONE);
-        } else {
-            mDefaultToolbarView.setVisibility(View.VISIBLE);
-        }
-    }
-
-    /**
-     * Determines if a touch event is inside the toolbar. This assumes the toolbar is the full
-     * width of the screen and that the toolbar is at the top of the bottom sheet.
-     * @param e The motion event to test.
-     * @return True if the event occured in the toolbar region.
-     */
-    private boolean isTouchEventInToolbar(MotionEvent e) {
-        if (mControlContainer == null) return false;
-
-        mControlContainer.getLocationInWindow(mLocationArray);
-
-        return e.getRawY() < mLocationArray[1] + mToolbarHeight;
-    }
-
-    /**
-     * A notification that the sheet is exiting the peek state into one that shows content.
-     */
-    private void onSheetOpened() {
-        for (BottomSheetObserver o : mObservers) o.onSheetOpened();
-    }
-
-    /**
-     * A notification that the sheet has returned to the peeking state.
-     */
-    private void onSheetClosed() {
-        for (BottomSheetObserver o : mObservers) o.onSheetClosed();
-    }
-
-    /**
-     * Creates an unadjusted version of a MotionEvent.
-     * @param e The original event.
-     * @return The unadjusted version of the event.
-     */
-    private MotionEvent createRawMotionEvent(MotionEvent e) {
-        MotionEvent rawEvent = MotionEvent.obtain(e);
-        rawEvent.setLocation(e.getRawX(), e.getRawY());
-        return rawEvent;
-    }
-
-    /**
-     * Updates the bottom sheet's peeking and content height.
-     */
-    private void updateSheetDimensions() {
-        if (mContainerHeight <= 0) return;
-
-        // Though mStateRatios is a static constant, the peeking ratio is computed here because
-        // the correct toolbar height and container height are not know until those views are
-        // inflated.
-        mStateRatios[0] = mToolbarHeight / mContainerHeight;
-
-        // Compute the height that the content section of the bottom sheet.
-        float contentHeight = (mContainerHeight * getFullRatio()) - mToolbarHeight;
-
-        MarginLayoutParams sheetContentParams =
-                (MarginLayoutParams) mBottomSheetContentContainer.getLayoutParams();
-        sheetContentParams.width = (int) mContainerWidth;
-        sheetContentParams.height = (int) contentHeight;
-        sheetContentParams.topMargin = (int) mToolbarHeight;
-
-        MarginLayoutParams toolbarShadowParams =
-                (MarginLayoutParams) findViewById(R.id.toolbar_shadow).getLayoutParams();
-        toolbarShadowParams.topMargin = (int) mToolbarHeight;
-
-        mBottomSheetContentContainer.requestLayout();
-    }
-
-    /**
-     * Cancels and nulls the height animation if it exists.
-     */
-    private void cancelAnimation() {
-        if (mSettleAnimator == null) return;
-        mSettleAnimator.cancel();
-        mSettleAnimator = null;
-    }
-
-    /**
-     * Creates the sheet's animation to a target state.
-     * @param targetState The target state.
-     */
-    private void createSettleAnimation(@SheetState int targetState) {
-        mCurrentState = targetState;
-        mSettleAnimator = ValueAnimator.ofFloat(getSheetOffsetFromBottom(),
-                getSheetHeightForState(targetState));
-        mSettleAnimator.setDuration(BASE_ANIMATION_DURATION_MS);
-        mSettleAnimator.setInterpolator(mInterpolator);
-
-        // When the animation is canceled or ends, reset the handle to null.
-        mSettleAnimator.addListener(new AnimatorListenerAdapter() {
-            @Override
-            public void onAnimationEnd(Animator animator) {
-                mSettleAnimator = null;
-            }
-        });
-
-        mSettleAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
-            @Override
-            public void onAnimationUpdate(ValueAnimator animator) {
-                setSheetOffsetFromBottom((Float) animator.getAnimatedValue());
-            }
-        });
-
-        mSettleAnimator.start();
-    }
-
-    /**
-     * Gets the distance of a fling based on the velocity and the base animation time. This formula
-     * assumes the deceleration curve is quadratic (t^2), hence the displacement formula should be:
-     * displacement = initialVelocity * duration / 2.
-     * @param velocity The velocity of the fling.
-     * @return The distance the fling would cover.
-     */
-    private float getFlingDistance(float velocity) {
-        // This includes conversion from seconds to ms.
-        return velocity * BASE_ANIMATION_DURATION_MS / 2000f;
-    }
-
-    /**
-     * Gets the maximum offset of the bottom sheet.
-     * @return The max offset.
-     */
-    private float getMaxOffset() {
-        return getFullRatio() * mContainerHeight;
-    }
-
-    /**
-     * Sets the sheet's offset relative to the bottom of the screen.
-     * @param offset The offset that the sheet should be.
-     */
-    private void setSheetOffsetFromBottom(float offset) {
-        if (MathUtils.areFloatsEqual(getSheetOffsetFromBottom(), getMinOffset())
-                && offset > getMinOffset()) {
-            onSheetOpened();
-        } else if (MathUtils.areFloatsEqual(offset, getMinOffset())
-                && getSheetOffsetFromBottom() > getMinOffset()) {
-            onSheetClosed();
-        }
-
-        setTranslationY(mContainerHeight - offset);
-        sendOffsetChangeEvents();
-    }
-
-    /**
-     * This is the same as {@link #setSheetOffsetFromBottom(float)} but exclusively for testing.
-     * @param offset The offset to set the sheet to.
-     */
-    @VisibleForTesting
-    public void setSheetOffsetFromBottomForTesting(float offset) {
-        setSheetOffsetFromBottom(offset);
-    }
-
-    /**
-     * @return The ratio of the height of the screen that the peeking state is.
-     */
-    @VisibleForTesting
-    public float getPeekRatio() {
-        return mStateRatios[0];
-    }
-
-    /**
-     * @return The ratio of the height of the screen that the half expanded state is.
-     */
-    @VisibleForTesting
-    public float getHalfRatio() {
-        return mStateRatios[1];
-    }
-
-    /**
-     * @return The ratio of the height of the screen that the fully expanded state is.
-     */
-    @VisibleForTesting
-    public float getFullRatio() {
-        return mStateRatios[2];
-    }
-
-    /**
-     * @return The height of the container that the bottom sheet exists in.
-     */
-    @VisibleForTesting
-    public float getSheetContainerHeight() {
-        return mContainerHeight;
-    }
-
-    /**
-     * Sends notifications if the sheet is transitioning from the peeking to half expanded state and
-     * from the peeking to fully expanded state. The peek to half events are only sent when the
-     * sheet is between the peeking and half states.
-     */
-    private void sendOffsetChangeEvents() {
-        float screenRatio =
-                mContainerHeight > 0 ? getSheetOffsetFromBottom() / mContainerHeight : 0;
-
-        // This ratio is relative to the peek and full positions of the sheet.
-        float peekFullRatio = MathUtils.clamp(
-                (screenRatio - getPeekRatio()) / (getFullRatio() - getPeekRatio()), 0, 1);
-
-        for (BottomSheetObserver o : mObservers) {
-            o.onSheetOffsetChanged(MathUtils.areFloatsEqual(peekFullRatio, 0) ? 0 : peekFullRatio);
-        }
-
-        // This ratio is relative to the peek and half positions of the sheet.
-        float peekHalfRatio = MathUtils.clamp(
-                (screenRatio - getPeekRatio()) / (getHalfRatio() - getPeekRatio()), 0, 1);
-
-        // If the ratio is close enough to zero, just set it to zero.
-        if (MathUtils.areFloatsEqual(peekHalfRatio, 0f)) peekHalfRatio = 0f;
-
-        if (mLastPeekToHalfRatioSent < 1f || peekHalfRatio < 1f) {
-            mLastPeekToHalfRatioSent = peekHalfRatio;
-            for (BottomSheetObserver o : mObservers) {
-                o.onTransitionPeekToHalf(peekHalfRatio);
-            }
-        }
-    }
-
-    /**
-     * Moves the sheet to the provided state.
-     * @param state The state to move the panel to.
-     * @param animate If true, the sheet will animate to the provided state, otherwise it will
-     *                move there instantly.
-     */
-    public void setSheetState(@SheetState int state, boolean animate) {
-        mCurrentState = state;
-
-        if (animate) {
-            createSettleAnimation(state);
-        } else {
-            setSheetOffsetFromBottom(getSheetHeightForState(state));
-        }
-    }
-
-    /**
-     * @return The current state of the bottom sheet. If the sheet is animating, this will be the
-     *         state the sheet is animating to.
-     */
-    public int getSheetState() {
-        return mCurrentState;
-    }
-
-    /**
-     * If the animation to settle the sheet in one of its states is running.
-     * @return True if the animation is running.
-     */
-    public boolean isRunningSettleAnimation() {
-        return mSettleAnimator != null;
-    }
-
-    @VisibleForTesting
-    public BottomSheetContent getCurrentSheetContent() {
-        return mSheetContent;
-    }
-
-    /**
-     * Gets the height of the bottom sheet based on a provided state.
-     * @param state The state to get the height from.
-     * @return The height of the sheet at the provided state.
-     */
-    private float getSheetHeightForState(@SheetState int state) {
-        return mStateRatios[state] * mContainerHeight;
-    }
-
-    /**
-     * Adds an observer to the bottom sheet.
-     * @param observer The observer to add.
-     */
-    public void addObserver(BottomSheetObserver observer) {
-        mObservers.addObserver(observer);
-    }
-
-    /**
-     * Gets the target state of the sheet based on the sheet's height and velocity.
-     * @param sheetHeight The current height of the sheet.
-     * @param yVelocity The current Y velocity of the sheet. This is only used for determining the
-     *                  scroll or fling direction. If this value is positive, the movement is from
-     *                  bottom to top.
-     * @return The target state of the bottom sheet.
-     */
-    private int getTargetSheetState(float sheetHeight, float yVelocity) {
-        if (sheetHeight <= getMinOffset()) return SHEET_STATE_PEEK;
-        if (sheetHeight >= getMaxOffset()) return SHEET_STATE_FULL;
-
-        // First, find the two states that the sheet height is between.
-        @SheetState
-        int nextState = sStates[0];
-
-        @SheetState
-        int prevState = nextState;
-        for (int i = 0; i < sStates.length; i++) {
-            prevState = nextState;
-            nextState = sStates[i];
-            // The values in PanelState are ascending, they should be kept that way in order for
-            // this to work.
-            if (sheetHeight >= getSheetHeightForState(prevState)
-                    && sheetHeight < getSheetHeightForState(nextState)) {
-                break;
-            }
-        }
-
-        // If the desired height is close enough to a certain state, depending on the direction of
-        // the velocity, move to that state.
-        float lowerBound = getSheetHeightForState(prevState);
-        float distance = getSheetHeightForState(nextState) - lowerBound;
-
-        float inverseThreshold = 1.0f - THRESHOLD_TO_NEXT_STATE;
-        float thresholdToNextState = yVelocity < 0.0f ? THRESHOLD_TO_NEXT_STATE : inverseThreshold;
-
-        if ((sheetHeight - lowerBound) / distance > thresholdToNextState) {
-            return nextState;
-        }
-        return prevState;
-    }
-
-    @Override
-    public void onFadingViewClick() {
-        setSheetState(SHEET_STATE_PEEK, true);
-    }
-
-    @Override
-    public void onFadingViewVisibilityChanged(boolean visible) {}
-
-    private boolean canMoveSheet() {
-        boolean isInOverviewMode = mTabModelSelector != null
-                && (mTabModelSelector.getCurrentTab() == null
-                           || mTabModelSelector.getCurrentTab().getActivity().isInOverviewMode());
-        return !isToolbarAndroidViewHidden() && !isInOverviewMode;
-    }
-}