Constraint Layout DOJO - Views without constraints (STEP 2)

comment.xml

<ImageView
    android:id="@+id/comment"
    android:layout_width="21dp"
    android:layout_height="21dp"
    android:layout_marginTop="12dp"

    android:src="@drawable/ic_comment"
    android:tint="@color/gray"/>

favorite.xml

<ImageView
    android:id="@+id/favorite"
    android:layout_width="21dp"
    android:layout_height="21dp"

    android:src="@drawable/ic_favorite"
    android:tint="@color/gray"/>

retweet.xml

<ImageView
    android:id="@+id/retweet"
    android:layout_width="21dp"
    android:layout_height="21dp"

    android:src="@drawable/ic_retweet"
    android:tint="@color/gray"/>

share.xml

<ImageView
    android:id="@+id/share"
    android:layout_width="21dp"
    android:layout_height="21dp"

    android:src="@drawable/ic_share"
    android:tint="@color/gray"/>