Update bottom sheet navigation selector during peeking -> half transition according to motion spec.

The navigation selector will now hide immediately when moving the
bottom sheet down from the half state (full state for small screens),
instead of 96dp before the peek position.

Preview: https://drive.google.com/open?id=0B8YGYtFin7saZ2VDNmhnZGZJWTg

Bug: 759130
Change-Id: I326d9baf0f8f837b782a51f6daa84c13fac1074a
Reviewed-on: https://chromium-review.googlesource.com/689999
Commit-Queue: Bernhard Bauer <bauerb@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505344}

chrome/android/java/res/values/dimens.xml

@@ -491,8 +491,6 @@
     <!-- Bottom sheet dimensions -->
     <dimen name="bottom_sheet_help_bubble_inset">10dp</dimen>
     <dimen name="bottom_nav_height">40dp</dimen>
-    <dimen name="bottom_nav_space_from_toolbar">96dp</dimen>
-    <!-- The following two dimensions override defaults in Android's BottomNavigationView -->
 
     <!-- Chrome Home dimensions -->
     <dimen name="chrome_home_empty_view_top_padding">72dp</dimen>

chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java

@@ -397,10 +397,7 @@ public abstract class ChromeActivity extends AsyncInitializationActivity
             mBottomSheetContentController =
                     (BottomSheetContentController) ((ViewStub) findViewById(R.id.bottom_nav_stub))
                             .inflate();
-            int controlContainerHeight =
-                    ((ControlContainer) findViewById(R.id.control_container)).getView().getHeight();
-            mBottomSheetContentController.init(
-                    mBottomSheet, controlContainerHeight, mTabModelSelector, this);
+            mBottomSheetContentController.init(mBottomSheet, mTabModelSelector, this);
         }
         ((BottomContainer) findViewById(R.id.bottom_container)).initialize(mFullscreenManager);
     }

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

@@ -1504,7 +1504,7 @@ public class BottomSheet
      * @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) {
+    public float getSheetHeightForState(@SheetState int state) {
         return mStateRatios[state] * mContainerHeight;
     }
 
@@ -1573,7 +1573,7 @@ public class BottomSheet
         return prevState;
     }
 
-    private boolean isSmallScreen() {
+    public boolean isSmallScreen() {
         // A small screen is defined by there being less than 160dp between half and full states.
         float fullToHalfDiff = (getFullRatio() - getHalfRatio()) * mContainerHeight;
         return fullToHalfDiff < mMinHalfFullDistance;

chrome/android/java/src/org/chromium/chrome/browser/widget/bottomsheet/BottomSheetContentController.java

@@ -7,7 +7,6 @@ package org.chromium.chrome.browser.widget.bottomsheet;
 import android.app.Activity;
 import android.content.Context;
 import android.content.res.ColorStateList;
-import android.content.res.Resources;
 import android.support.annotation.IntDef;
 import android.support.annotation.Nullable;
 import android.util.AttributeSet;
@@ -89,9 +88,10 @@ public class BottomSheetContentController extends BottomNavigationView
         public void onSheetOffsetChanged(float heightFraction) {
             // If the omnibox is not focused, allow the navigation bar to set its Y translation.
             if (!mOmniboxHasFocus) {
-                float offsetY =
-                        (mBottomSheet.getMinOffset() - mBottomSheet.getSheetOffsetFromBottom())
-                        + mDistanceBelowToolbarPx;
+                float offsetY = mBottomSheet.getSheetHeightForState(mBottomSheet.isSmallScreen()
+                                                ? BottomSheet.SHEET_STATE_FULL
+                                                : BottomSheet.SHEET_STATE_HALF)
+                        - mBottomSheet.getSheetOffsetFromBottom();
                 setTranslationY(Math.max(offsetY, 0f));
 
                 if (mBottomSheet.getTargetSheetState() != BottomSheet.SHEET_STATE_PEEK
@@ -172,7 +172,6 @@ public class BottomSheetContentController extends BottomNavigationView
     private BottomSheet mBottomSheet;
     private TabModelSelector mTabModelSelector;
     private SnackbarManager mSnackbarManager;
-    private float mDistanceBelowToolbarPx;
     private int mSelectedItemId;
     private ChromeActivity mActivity;
     private boolean mShouldOpenSheetOnNextContentChange;
@@ -209,12 +208,11 @@ public class BottomSheetContentController extends BottomNavigationView
     /**
      * Initializes the {@link BottomSheetContentController}.
      * @param bottomSheet The {@link BottomSheet} associated with this bottom nav.
-     * @param controlContainerHeight The height of the control container in px.
      * @param tabModelSelector The {@link TabModelSelector} for the application.
      * @param activity The {@link ChromeActivity} that owns the BottomSheet.
      */
-    public void init(BottomSheet bottomSheet, int controlContainerHeight,
-            TabModelSelector tabModelSelector, ChromeActivity activity) {
+    public void init(
+            BottomSheet bottomSheet, TabModelSelector tabModelSelector, ChromeActivity activity) {
         mBottomSheet = bottomSheet;
         mBottomSheet.addObserver(mBottomSheetObserver);
         mActivity = activity;
@@ -236,10 +234,6 @@ public class BottomSheetContentController extends BottomNavigationView
         };
         mTabModelSelector.addObserver(mTabModelSelectorObserver);
 
-        Resources res = getContext().getResources();
-        mDistanceBelowToolbarPx = controlContainerHeight
-                + res.getDimensionPixelOffset(R.dimen.bottom_nav_space_from_toolbar);
-
         setOnNavigationItemSelectedListener(this);
         hideMenuLabels();