Use the same shadow for the Android NTP fakebox than for the top omnibox.

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageLayout.java

 // 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.ntp;
 
 import android.content.Context;
 import android.content.res.Resources;
+import android.graphics.Rect;
+import android.graphics.drawable.Drawable;
 import android.util.AttributeSet;
 import android.view.View;
 import android.widget.LinearLayout;
 
-import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.chrome.R;
 
 /**
  * Layout for the new tab page. This positions the page elements in the correct vertical positions.
  * There are no separate phone and tablet UIs; this layout adapts based on the available space.
  */
 public class NewTabPageLayout extends LinearLayout {
 
     // Space permitting, the spacers will grow from 0dp to the heights given below. If there is
     // additional space, it will be distributed evenly between the top and bottom spacers.
     private static final float TOP_SPACER_HEIGHT_DP = 44f;
     private static final float MIDDLE_SPACER_HEIGHT_DP = 24f;
     private static final float BOTTOM_SPACER_HEIGHT_DP = 44f;
     private static final float TOTAL_SPACER_HEIGHT_DP = TOP_SPACER_HEIGHT_DP
             + MIDDLE_SPACER_HEIGHT_DP + BOTTOM_SPACER_HEIGHT_DP;
 
     private final int mTopSpacerIdealHeight;
     private final int mMiddleSpacerIdealHeight;
     private final int mBottomSpacerIdealHeight;
     private final int mTotalSpacerIdealHeight;
     private final int mMostVisitedLayoutBleed;
     private final int mPeekingCardHeight;
     private final int mTabStripHeight;
 
     private int mParentViewportHeight;
+    private int mSearchboxViewShadowWidth;
 
     private boolean mCardsUiEnabled;
     private View mTopSpacer;  // Spacer above search logo.
     private View mMiddleSpacer;  // Spacer between toolbar and Most Likely.
     private View mBottomSpacer;  // Spacer below Most Likely.
 
     // Separate spacer below Most Likely to add enough space so the user can scroll with Most Likely
     // at the top of the screen.
     private View mScrollCompensationSpacer;
 
     private LogoView mSearchProviderLogoView;
     private View mSearchBoxView;
     private MostVisitedLayout mMostVisitedLayout;
-

[Theresa, 2016/05/26 21:54:41]

nit: please add this line back.

     /**
      * Constructor for inflating from XML.
      */
     public NewTabPageLayout(Context context, AttributeSet attrs) {
         super(context, attrs);
         Resources res = getResources();
         float density = res.getDisplayMetrics().density;
         mTopSpacerIdealHeight = Math.round(density * TOP_SPACER_HEIGHT_DP);
         mMiddleSpacerIdealHeight = Math.round(density * MIDDLE_SPACER_HEIGHT_DP);
         mBottomSpacerIdealHeight = Math.round(density * BOTTOM_SPACER_HEIGHT_DP);
@@ skipping 72 matching lines @@
                         mParentViewportHeight - mPeekingCardHeight - mTabStripHeight);
                 // Call onMeasure to update mTopScaper's height.
                 super.onMeasure(widthMeasureSpec, heightMeasureSpec);
             }
             distributeExtraSpace(mTopSpacer.getMeasuredHeight());
         }
 
         // Make the search box and logo as wide as the most visited items.
         if (mMostVisitedLayout.getVisibility() != GONE) {
             final int width = mMostVisitedLayout.getMeasuredWidth() - mMostVisitedLayoutBleed;
-            setMeasure(mSearchBoxView, width, mSearchBoxView.getMeasuredHeight());
+            setMeasure(mSearchBoxView, width + mSearchboxViewShadowWidth,
+                    mSearchBoxView.getMeasuredHeight());
             setMeasure(mSearchProviderLogoView, width, mSearchProviderLogoView.getMeasuredHeight());
         }
     }
 
     /**
      * Calculate the vertical position of Most Visited.
      * This method does not use mMostVisitedLayout.getTop(), so can be called in onMeasure.
      */
     private int calculateTopOfMostVisited() {
         // Manually add the heights (and margins) of all children above Most Visited.
         int top = 0;
         int mostVisitedIndex = indexOfChild(mMostVisitedLayout);
         for (int i = 0; i < mostVisitedIndex; i++) {
             View child = getChildAt(i);
             MarginLayoutParams params = (MarginLayoutParams) child.getLayoutParams();
 
             if (child.getVisibility() != View.GONE) {
                 top += params.topMargin + child.getMeasuredHeight() + params.bottomMargin;
             }
         }
         top += ((MarginLayoutParams) mMostVisitedLayout.getLayoutParams()).topMargin;
         return top;
     }
 
     /**
-     * Set the search box style. Modify the search box to enable material when snippets or
-     * material design is enabled.
+     * Set the search box style, adding a shadow if required.
      */
     private void setSearchBoxStyle() {
-        if (NtpColorUtils.shouldUseMaterialColors()
-                && ApiCompatibilityUtils.setElevation(mSearchBoxView,
-                           getResources().getDimensionPixelSize(R.dimen.toolbar_elevation))) {
-            // Replace drawable with one that does not contain a border.
-            mSearchBoxView.setBackgroundResource(R.drawable.bg_ntp_search_box_material);
-        }
+        if (!NtpColorUtils.shouldUseMaterialColors()) return;
+
+        Drawable background = mSearchBoxView.getBackground();

[Theresa, 2016/05/26 17:47:26]

Can the padding be added via xml? I'm hoping we can avoid all of this manual
calculation.

Since the current background (R.drawable.bg_ntp_search_box) is just being
replaced with R.drawable.textbox, can we change new_tab_page_layout.xml to use
R.drawable.textbox as the search_box background instead?

Just to double check, the screenshots in the email thread were using
R.drawable.textbox as the background?

[Bernhard Bauer, 2016/05/26 19:43:57]

The reason I'm doing this in code is that we still have a flag to turn this off
(the shadow goes with the more-material NTP background). Once that flag is
removed, I can switch over to doing everything in XML.
That's correct.

[Theresa, 2016/05/26 21:54:41]

Can you use defined dimens that represent the correct new layout params/padding
instead of calculating it?

[Bernhard Bauer, 2016/05/27 12:16:41]

Done. Note however that keeping the exactly same positioning of e.g. the search
box contents isn't possible without calculations, because the padding for the
default background is specified in pixels, whereas the padding for the
nine-patch is in dp. I've adjusted the values so that it looks as closely to the
original on an XXHDPI device as possible without having to go into fractional
dp's.

+        Rect padding = new Rect();
+        background.getPadding(padding);
+
+        Resources resources = getContext().getResources();
+        Drawable shadow = resources.getDrawable(R.drawable.textbox);

[Theresa, 2016/05/26 21:54:41]

Resources.getDrawable() is deprecated. Use ApiCompatibilityUtils#getDrawable().

[Bernhard Bauer, 2016/05/27 12:16:41]

Thanks! That code is gone now though.

+        Rect shadowPadding = new Rect();
+        shadow.getPadding(shadowPadding);
+
+        // Adjust the margins to remove the padding.

[Theresa, 2016/05/26 21:54:41]

Why does the padding need to be removed just to be added back?

[Bernhard Bauer, 2016/05/27 12:16:41]

Sorry, that comment should have been a bit more detailed. The |textbox| drawable
extends further than the default one does, because it includes the shadow. So,
in order to keep the apparent border and the contents in the same position, I
have to subtract the extrusion value (which is the |textbox| drawable's padding)
from the margins but add them to the existing padding for the default
background. Anyway, that code is gone now.

+        MarginLayoutParams layoutParams = (MarginLayoutParams) mSearchBoxView.getLayoutParams();
+        layoutParams.topMargin -= shadowPadding.top;
+        layoutParams.bottomMargin -= shadowPadding.bottom;
+        layoutParams.leftMargin -= shadowPadding.left;
+        layoutParams.rightMargin -= shadowPadding.right;
+        layoutParams.height += shadowPadding.bottom + shadowPadding.top;
+        // Width will be adjusted in onMeasure();
+        mSearchboxViewShadowWidth = shadowPadding.left + shadowPadding.right;
+
+        // Add the extra padding back.
+        mSearchBoxView.setBackground(shadow);
+        mSearchBoxView.setPadding(
+                padding.left + shadowPadding.left,
+                padding.top + shadowPadding.top,
+                padding.right + shadowPadding.right,
+                padding.bottom + shadowPadding.bottom);
     }
 
     /**
      * Distribute extra vertical space between the three spacer views.
      * @param extraHeight The amount of extra space, in pixels.
      */
     private void distributeExtraSpace(int extraHeight) {
         int topSpacerHeight;
         int middleSpacerHeight;
         int bottomSpacerHeight;
@@ skipping 21 matching lines @@
 
     /**
      * Convenience method to call |measure| on the given View with MeasureSpecs converted from the
      * given dimensions (in pixels) with MeasureSpec.EXACTLY.
      */
     private void setMeasure(View view, int widthPx, int heightPx) {
         view.measure(MeasureSpec.makeMeasureSpec(widthPx, MeasureSpec.EXACTLY),
                 MeasureSpec.makeMeasureSpec(heightPx, MeasureSpec.EXACTLY));
     }
 }