Set article spacing in dp, not px.

chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetItemDecoration.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetItemDecoration.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetItemDecoration.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetItemDecoration.java
index e7590a127ebfbda10365ba73f848266fadee88a6..da0719b053036e8a39bf6d07e491c9fce4132696 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetItemDecoration.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetItemDecoration.java
@@ -4,25 +4,69 @@
 
 package org.chromium.chrome.browser.ntp.snippets;
 
+import android.content.Context;
+import android.graphics.Canvas;
 import android.graphics.Rect;
+import android.graphics.drawable.Drawable;
+import android.support.v4.content.res.ResourcesCompat;
 import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.RecyclerView.Adapter;
 import android.view.View;
 
+import org.chromium.chrome.R;
+import org.chromium.chrome.browser.ntp.cards.NewTabPageListItem;
+
 /**
- * A class that decorates the RecyclerView elements.
+ * A decorator that places separators between RecyclerView items of type
+ * {@value NewTabPageListItem#VIEW_TYPE_SNIPPET}.
  */
 public class SnippetItemDecoration extends RecyclerView.ItemDecoration {
-    private static final int VERTICAL_SPACE = 1;
+    private final Drawable mSeparator;
+
+    public SnippetItemDecoration(Context context) {
+        mSeparator = ResourcesCompat
+                .getDrawable(context.getResources(), R.drawable.snippet_separator, null);
+    }
 
     @Override
     public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
             RecyclerView.State state) {
-        // Reset the bounds of the outRect.
-        outRect.setEmpty();
+        if (!shouldPlaceSeparator(view, parent)) return;
+
+        // Add space below the item to show the separator.
+        outRect.set(0, 0, 0, mSeparator.getIntrinsicHeight());
+    }
+
+    @Override
+    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
+        final int left = parent.getPaddingLeft();
+        final int right = parent.getWidth() - parent.getPaddingRight();
 
-        // Do not add a vertical space to the last item.
-        if (parent.getChildAdapterPosition(view) != parent.getAdapter().getItemCount() - 1) {
-            outRect.bottom = VERTICAL_SPACE;
+        // Draw the separators underneath the relevant items.
+        for (int i = 0; i < parent.getChildCount(); i++) {
+            View child = parent.getChildAt(i);
+            if (!shouldPlaceSeparator(child, parent)) continue;
+
+            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
+            final int top = child.getBottom() + params.bottomMargin;
+            final int bottom = top + mSeparator.getIntrinsicHeight();
+
+            mSeparator.setBounds(left, top, right, bottom);
+            mSeparator.draw(c);
         }
     }
+
+    /**
+     * Checks whether there should be a separator below the given view in the RecyclerView.
+     * Current logic checks if the current view and next view show snippets.
+     */
+    private boolean shouldPlaceSeparator(View view, RecyclerView parent) {
+        int childPos = parent.getChildAdapterPosition(view);
+        Adapter adapter = parent.getAdapter();
+
+        if (childPos == adapter.getItemCount() - 1) return false;
+
+        return adapter.getItemViewType(childPos) == NewTabPageListItem.VIEW_TYPE_SNIPPET
+                && adapter.getItemViewType(childPos + 1) == NewTabPageListItem.VIEW_TYPE_SNIPPET;
+    }
 }