title: Padding reduces Icon size in ImageView
body: <p>I want ripple effect on my icon. But when i increase padding it reduces the icon size 
  when padding is 5dp it looks something like this <a href="https://i.stack.imgur.com/n8BDx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/n8BDx.png" alt="enter image description here"></a></p>
  
  <p>But when i increase padding size to 12dp it looks like this <a href="https://i.stack.imgur.com/0Evvb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0Evvb.png" alt="enter image description here"></a></p>
  
  <p>My ImageView xml </p>
  
  <pre><code> &lt;ImageView
              android:id="@+id/institute_search_item_request_icon"
              android:layout_width="40dp"
              android:layout_height="40dp"
              android:layout_alignParentEnd="true"
              android:layout_marginEnd="20dp"
              android:layout_marginTop="15dp"
              android:background="@drawable/request_institute_red_icon__shape"
              android:foreground="@drawable/ripple_foreground"
              android:padding="12dp"
              android:src="@drawable/ic_link_white_24dp" /&gt;
  </code></pre>
  
  <p>request_institute_red_icon__shape.xml</p>
  
  <pre><code>&lt;shape xmlns:android="http://schemas.android.com/apk/res/android"
  android:shape="oval"&gt;
  
  &lt;solid android:color="@color/colorPrimary" /&gt;
  </code></pre>
  
  <p></p>
  
  <p>and ripple_foreground.xml</p>
  
  <pre><code>&lt;ripple xmlns:android="http://schemas.android.com/apk/res/android"
  android:color="@color/colorAccent"&gt;
  &lt;item android:id="@android:id/mask"&gt;
      &lt;shape android:shape="oval"&gt;
          &lt;solid android:color="@color/colorPrimary" /&gt;
      &lt;/shape&gt;
  &lt;/item&gt;
  </code></pre>
  
  <p></p>