added scale animation for context menu

chrome/android/java/src/org/chromium/chrome/browser/contextmenu/TabularContextMenuViewPager.java

 // 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.contextmenu;
 
 import android.content.Context;
 import android.support.v4.view.ViewPager;
 import android.util.AttributeSet;
 import android.view.View;
 
 import org.chromium.chrome.R;
 
 /**
  * When there is more than one view for the context menu to display, it wraps the display in a view
  * pager.
  */
 public class TabularContextMenuViewPager extends ViewPager {
+    private static final double MAX_WIDTH_PROPORTION = 0.75;
+
     public TabularContextMenuViewPager(Context context) {
         super(context);
     }
 
     public TabularContextMenuViewPager(Context context, AttributeSet attrs) {
         super(context, attrs);
     }
 
     /**
      * Used to show the full ViewPager dialog. Without this the dialog would have no height or
      * width.
      */
     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         int menuHeight = 0;
         int tabHeight = 0;
+
         // getCurrentItem() does not take into account the tab layout unlike getChildCount().
         int currentItemsIndex = getCurrentItem() + 1;
 
+        // TODO(injae): Fix sizing on orientation changes (crbug.com/731173)
+        int contextMenuWidth = (int) Math.min(
+                getResources().getDisplayMetrics().widthPixels * MAX_WIDTH_PROPORTION,
+                getResources().getDimensionPixelSize(R.dimen.context_menu_max_width));
+
+        widthMeasureSpec = MeasureSpec.makeMeasureSpec(contextMenuWidth, MeasureSpec.EXACTLY);
+
         for (int i = 0; i < getChildCount(); i++) {
             View child = getChildAt(i);
+
             child.measure(
                     widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
             int measuredHeight = child.getMeasuredHeight();
 
             // The ViewPager also considers the tab layout one of its children, and needs to be
             // treated separately from getting the largest height.
             if (child.getId() == R.id.tab_layout && child.getVisibility() != GONE) {
                 tabHeight = measuredHeight;
             } else if (i == currentItemsIndex) {
                 menuHeight = child.getMeasuredHeight();
                 break;
             }
         }
         int fullHeight = menuHeight + tabHeight;
 
         heightMeasureSpec = MeasureSpec.makeMeasureSpec(fullHeight, MeasureSpec.EXACTLY);
         super.onMeasure(widthMeasureSpec, heightMeasureSpec);
     }
 }