Merge branch 'main' into compute_intersection_return

Author: szager-chromium

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,11 @@
+Closes #???
+
+The following tasks have been completed:
+
+ * [ ] Modified Web platform tests (link to pull request)
+
+Implementation commitment:
+
+ * [ ] WebKit (https://bugs.webkit.org/show_bug.cgi?id=)
+ * [ ] Chromium (https://bugs.chromium.org/p/chromium/issues/detail?id=)
+ * [ ] Gecko (https://bugzilla.mozilla.org/show_bug.cgi?id=)

.github/workflows/auto-publish.yml

@@ -0,0 +1,22 @@
+name: CI
+on:
+  pull_request: {}
+  push:
+    branches: [main]
+jobs:
+  main:
+    name: Build, Validate, Deploy
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: w3c/spec-prod@v2
+        with:
+          GH_PAGES_BRANCH: gh-pages
+          TOOLCHAIN: bikeshed
+          BUILD_FAIL_ON: "link-error"
+          W3C_NOTIFICATIONS_CC: ${{ secrets.CC }}
+          W3C_ECHIDNA_TOKEN: ${{ secrets.ECHIDNA_TOKEN }}
+          W3C_WG_DECISION_URL: https://lists.w3.org/Archives/Public/public-webapps/2014JulSep/0627.html
+          W3C_BUILD_OVERRIDE: |
+            status: WD
+            shortname: intersection-observer

.travis.yml

@@ -4,7 +4,7 @@ Implementation status:
   - Chromium: [Shipped in Chrome 51](https://www.chromestatus.com/feature/5695342691483648)
   - Edge: [Shipped in build 14986](https://developer.microsoft.com/en-us/microsoft-edge/platform/status/intersectionobserver/)
   - Firefox: [Shipped in Firefox 55](https://platform-status.mozilla.org/#intersection-observer)
-  - WebKit: [Under development](https://bugs.webkit.org/show_bug.cgi?id=159475)
+  - WebKit: [Shipped in Safari 12.1 and iOS 12.2](https://developer.apple.com/documentation/safari_release_notes/safari_12_1_release_notes#3130314)
 
 [Explainer Doc](./explainer.md)
 

README.md

@@ -6,13 +6,13 @@ This repo outlines an API that can be used to understand movement of DOM element
 
 ## Observing Position
 
-The web's traditional position calculation mechanisms rely on explicit queries of DOM state. Some of these are known to cause style recalcuation and layout and, frequently, are redundant thanks to the requirement that scripts poll for this information.
+The web's traditional position calculation mechanisms rely on explicit queries of DOM state. Some of these are known to cause style recalculation and layout and, frequently, are redundant thanks to the requirement that scripts poll for this information.
 
 A body of common practice has evolved that relies on these behaviors, however, including (but not limited to):
 
   * Observing the location of "below the fold" sections of content in order to lazy-load content.
   * Implementing data-bound high-performance scrolling lists which load and render subsets of data sets. These lists are a central mobile interaction idiom.
-  * Calculating element visibility. In particular, [ad networks now require reporting of ad "visibility" for monetizing impressions](http://www.iab.net/iablog/2014/03/viewability-has-arrived-what-you-need-to-know-to-see-through-this-sea-change.html). This has led to many sites abusing scroll handlers, [synchronous layout invoking readbacks](http://gent.ilcore.com/2011/03/how-not-to-trigger-layout-in-webkit.html), and resorting to exotic plugin-based solutions for computing "true" element visibility (as a fraction of the element's intended size).
+  * Calculating element visibility. In particular, [ad networks now require reporting of ad "visibility" for monetizing impressions](https://www.iab.com/news/viewability-has-arrived-what-you-need-to-know-to-see-through-this-sea-change/). This has led to many sites abusing scroll handlers, [synchronous layout invoking readbacks](https://gist.github.com/paulirish/5d52fb081b3570c81e3a), and resorting to exotic plugin-based solutions for computing "true" element visibility (as a fraction of the element's intended size).
 
 These use-cases have several common properties:
 
@@ -164,7 +164,7 @@ function init() {
   // Notify when a scroll-item gets within, or moves beyond, 500px from the visible scroll surface.
   var opts = { 
     root: document.querySelector(".container"),
-    rootMargin: "500px 0px" 
+    rootMargin: "500px 0px"
   };
   var observer = new IntersectionObserver(manageItemPositionChanges, opts);
   // Set up observer on the items