Storyboard with autolayout constraints for aspect-fit of a subview in a container view, for http://stackoverflow.com/a/25768875/77567

Main.storyboard

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="6245" systemVersion="13E28" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" initialViewController="vXZ-lx-hvc">
    <dependencies>
        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="6238"/>
        <capability name="Aspect ratio constraints" minToolsVersion="5.1"/>
    </dependencies>
    <scenes>
        <!--View Controller-->
        <scene sceneID="ufC-wZ-h7g">
            <objects>
                <viewController id="vXZ-lx-hvc" customClass="ViewController" sceneMemberID="viewController">
                    <layoutGuides>
                        <viewControllerLayoutGuide type="top" id="jyV-Pf-zRb"/>
                        <viewControllerLayoutGuide type="bottom" id="2fi-mo-0CV"/>
                    </layoutGuides>
                    <view key="view" contentMode="scaleToFill" id="kh9-bI-dsS">
                        <rect key="frame" x="0.0" y="0.0" width="320" height="568"/>
                        <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                        <subviews>
                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="Bu0-Vn-NWW" userLabel="Top Container">
                                <rect key="frame" x="0.0" y="20" width="320" height="274"/>
                                <subviews>
                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="ccj-6U-TOq" userLabel="Top Fixed">
                                        <rect key="frame" x="0.0" y="97" width="320" height="80"/>
                                        <color key="backgroundColor" red="0.7743756422945951" green="1" blue="0.84614103840741328" alpha="1" colorSpace="calibratedRGB"/>
                                        <constraints>
                                            <constraint firstAttribute="width" secondItem="ccj-6U-TOq" secondAttribute="height" multiplier="4:1" id="Fzk-E3-Yi4"/>
                                        </constraints>
                                    </view>
                                </subviews>
                                <color key="backgroundColor" name="selectedTextBackgroundColor" catalog="System" colorSpace="catalog"/>
                                <constraints>
                                    <constraint firstAttribute="centerY" secondItem="ccj-6U-TOq" secondAttribute="centerY" id="C7Z-mZ-O3F"/>
                                    <constraint firstAttribute="width" secondItem="ccj-6U-TOq" secondAttribute="width" priority="750" id="Qxx-zD-gG3"/>
                                    <constraint firstAttribute="centerX" secondItem="ccj-6U-TOq" secondAttribute="centerX" id="Sgv-83-zCu"/>
                                    <constraint firstAttribute="width" relation="greaterThanOrEqual" secondItem="ccj-6U-TOq" secondAttribute="width" id="Tfk-Wb-vm1"/>
                                    <constraint firstAttribute="height" relation="greaterThanOrEqual" secondItem="ccj-6U-TOq" secondAttribute="height" id="dCD-Gj-ceM"/>
                                    <constraint firstAttribute="height" secondItem="ccj-6U-TOq" secondAttribute="height" priority="750" id="zCK-iT-3h7"/>
                                </constraints>
                            </view>
                            <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="oDr-sV-87W" userLabel="Bottom Container">
                                <rect key="frame" x="0.0" y="294" width="320" height="274"/>
                                <subviews>
                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="XyP-yL-Qrj" userLabel="Bottom Fixed">
                                        <rect key="frame" x="126" y="0.0" width="68" height="274"/>
                                        <color key="backgroundColor" red="0.41869353783065227" green="0.78573421556122447" blue="0.31103480678290174" alpha="1" colorSpace="calibratedRGB"/>
                                        <constraints>
                                            <constraint firstAttribute="width" secondItem="XyP-yL-Qrj" secondAttribute="height" multiplier="1:4" id="jgN-UY-age"/>
                                        </constraints>
                                    </view>
                                </subviews>
                                <color key="backgroundColor" red="0.99919813871383667" green="0.79837877270746882" blue="0.94132425558109956" alpha="1" colorSpace="calibratedRGB"/>
                                <constraints>
                                    <constraint firstItem="XyP-yL-Qrj" firstAttribute="width" secondItem="oDr-sV-87W" secondAttribute="width" priority="750" id="8Ag-aD-4Vm"/>
                                    <constraint firstItem="XyP-yL-Qrj" firstAttribute="height" secondItem="oDr-sV-87W" secondAttribute="height" priority="750" id="C1o-8f-d4N"/>
                                    <constraint firstItem="XyP-yL-Qrj" firstAttribute="width" relation="lessThanOrEqual" secondItem="oDr-sV-87W" secondAttribute="width" id="Mmc-hg-yyn"/>
                                    <constraint firstItem="XyP-yL-Qrj" firstAttribute="height" relation="lessThanOrEqual" secondItem="oDr-sV-87W" secondAttribute="height" id="SvR-cW-nsE"/>
                                    <constraint firstAttribute="centerX" secondItem="XyP-yL-Qrj" secondAttribute="centerX" id="cNG-5z-fBM"/>
                                    <constraint firstAttribute="centerY" secondItem="XyP-yL-Qrj" secondAttribute="centerY" id="of3-X1-PHi"/>
                                </constraints>
                            </view>
                        </subviews>
                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>
                        <constraints>
                            <constraint firstItem="2fi-mo-0CV" firstAttribute="top" secondItem="oDr-sV-87W" secondAttribute="bottom" id="8VZ-Ry-apK"/>
                            <constraint firstAttribute="trailing" secondItem="oDr-sV-87W" secondAttribute="trailing" id="9PA-G3-NcL"/>
                            <constraint firstItem="oDr-sV-87W" firstAttribute="top" secondItem="Bu0-Vn-NWW" secondAttribute="bottom" id="BCy-kB-avG"/>
                            <constraint firstItem="Bu0-Vn-NWW" firstAttribute="top" secondItem="jyV-Pf-zRb" secondAttribute="bottom" id="Hg6-Po-05K"/>
                            <constraint firstItem="Bu0-Vn-NWW" firstAttribute="leading" secondItem="kh9-bI-dsS" secondAttribute="leading" id="PRq-z7-Ugj"/>
                            <constraint firstAttribute="trailing" secondItem="Bu0-Vn-NWW" secondAttribute="trailing" id="aqe-SH-y7a"/>
                            <constraint firstItem="oDr-sV-87W" firstAttribute="leading" secondItem="kh9-bI-dsS" secondAttribute="leading" id="guo-VL-Y9e"/>
                            <constraint firstItem="Bu0-Vn-NWW" firstAttribute="height" secondItem="oDr-sV-87W" secondAttribute="height" id="vXe-Dl-wSQ"/>
                        </constraints>
                    </view>
                </viewController>
                <placeholder placeholderIdentifier="IBFirstResponder" id="x5A-6p-PRh" sceneMemberID="firstResponder"/>
            </objects>
            <point key="canvasLocation" x="1514" y="1336"/>
        </scene>
    </scenes>
    <simulatedMetricsContainer key="defaultSimulatedMetrics">
        <simulatedStatusBarMetrics key="statusBar"/>
        <simulatedOrientationMetrics key="orientation"/>
        <simulatedScreenMetrics key="destination" type="retina4"/>
    </simulatedMetricsContainer>
</document>