You can use setlogo method in toolbar to fill the your desired space
toolbar.setLogo(R.drawable.yourlogo);
or simply set all icon inside your toolbar according to your requirement.
like this
<android.support.v7.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize">
<LinearLayout
android:layout_width="wrap_content"
android:orientation="horizontal"
android:layout_height="wrap_content">
<ImageView
android:layout_width="wrap_content"
android:background="@mipmap/ic_launcher"
android:layout_height="wrap_content" />
<ImageView
android:layout_width="wrap_content"
android:background="@mipmap/ic_launcher"
android:layout_height="wrap_content" />
<ImageView
android:layout_width="wrap_content"
android:background="@mipmap/ic_launcher"
android:layout_height="wrap_content" />
<ImageView
android:layout_width="wrap_content"
android:background="@mipmap/ic_launcher"
android:layout_height="wrap_content" />
<ImageView
android:layout_width="wrap_content"
android:background="@mipmap/ic_launcher"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.Toolbar>
Hope this help!