Sensor.timestamp: Account for "get value from latest reading" returning null (#480)

SHA: 0a4fd13
Reason: push, by rakuco

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: Raphael Kubo da Costa

index.html

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    <h1 class="p-name no-ref" id="title">Generic Sensor API</h1>
-   <p id="w3c-state"><a href="https://www.w3.org/standards/types#ED">Editor’s Draft</a>, <time class="dt-updated" datetime="2024-01-25">25 January 2024</time></p>
+   <p id="w3c-state"><a href="https://www.w3.org/standards/types#ED">Editor’s Draft</a>, <time class="dt-updated" datetime="2024-02-17">17 February 2024</time></p>
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     <summary>More details about this document</summary>
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@@ -1869,7 +1869,9 @@ <h4 class="heading settled" data-level="7.1.6" id="sensor-timestamp"><span class
      <li data-md>
       <p>Let <var>unsafeTimestamp</var> be the result of invoking <a data-link-type="dfn" href="#get-value-from-latest-reading" id="ref-for-get-value-from-latest-reading②">get value from latest reading</a> with <a data-link-type="dfn" href="https://webidl.spec.whatwg.org/#this" id="ref-for-this③">this</a> and "timestamp" as arguments.</p>
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-      <p>Return <a data-link-type="dfn" href="https://w3c.github.io/hr-time/#dfn-relative-high-resolution-time" id="ref-for-dfn-relative-high-resolution-time">relative high resolution time</a> with <var>unsafeTimestamp</var> and <var>global</var>.</p>
+      <p>If <var>unsafeTimestamp</var> is null, return null.</p>
+     <li data-md>
+      <p>Otherwise, return <a data-link-type="dfn" href="https://w3c.github.io/hr-time/#dfn-relative-high-resolution-time" id="ref-for-dfn-relative-high-resolution-time">relative high resolution time</a> with <var>unsafeTimestamp</var> and <var>global</var>.</p>
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    <h4 class="heading settled" data-level="7.1.7" id="sensor-start"><span class="secno">7.1.7. </span><span class="content">Sensor.start()</span><a class="self-link" href="#sensor-start"></a></h4>
@@ -3578,7 +3580,7 @@ <h3 class="no-num no-ref heading settled" id="informative"><span class="content"
    <dt id="biblio-accelprint">[ACCELPRINT]
    <dd>Dey, Sanorita, et al.. <a href="http://synrg.csl.illinois.edu/papers/AccelPrint_NDSS14.pdf"><cite>AccelPrint: Imperfections of Accelerometers Make Smartphones Trackable</cite></a>. 2014. Informational. URL: <a href="http://synrg.csl.illinois.edu/papers/AccelPrint_NDSS14.pdf">http://synrg.csl.illinois.edu/papers/AccelPrint_NDSS14.pdf</a>
    <dt id="biblio-api-design-principles">[API-DESIGN-PRINCIPLES]
-   <dd>Sangwhan Moon. <a href="https://w3ctag.github.io/design-principles/"><cite>Web Platform Design Principles</cite></a>. URL: <a href="https://w3ctag.github.io/design-principles/">https://w3ctag.github.io/design-principles/</a>
+   <dd>Sangwhan Moon; Lea Verou. <a href="https://w3ctag.github.io/design-principles/"><cite>Web Platform Design Principles</cite></a>. URL: <a href="https://w3ctag.github.io/design-principles/">https://w3ctag.github.io/design-principles/</a>
    <dt id="biblio-coordinates-transformation">[COORDINATES-TRANSFORMATION]
    <dd>George W. Collins, II. <a href="http://ads.harvard.edu/books/1989fcm..book/Chapter2.pdf"><cite>The Foundations of Celestial Mechanics</cite></a>. 2004. Informational. URL: <a href="http://ads.harvard.edu/books/1989fcm..book/Chapter2.pdf">http://ads.harvard.edu/books/1989fcm..book/Chapter2.pdf</a>
    <dt id="biblio-extennnnsible">[EXTENNNNSIBLE]