Update changelog for merge of visibility:hidden fix to M88

Bug: 1141739
Change-Id: Ia8fd23a17e85c8da88c8384c9f6ef43ddb992b95
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2614408Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Annie Sullivan <sullivan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841086}

docs/speed/metrics_changelog/2020_11_cls.md

@@ -26,6 +26,15 @@ Going forward, there should be no CLS penalty for such elements. (Note that
 there still may be a layout shift for onscreen elements adjacent to (but not
 descendants of) the `content-visibility: auto` element.
 
+### Ignore layout shift when visibility:hidden becomes visible
+
+We have been always ignoring layout shifts when the element has
+visibility:hidden. However before Chrome 89, if the element having
+visibility:hidden became visible and shift at the same time, we reported layout
+shift. Now we also consider the previous visibility and ignore layout shift in
+the case.
+[Source code for this change](https://chromium-review.googlesource.com/c/chromium/src/+/2591367)
+
 ## How does this affect a site's metrics?
 
 All of these changes only affect sites with specific types of content. Here are
@@ -47,6 +56,11 @@ Sites using `content-visibility: auto` should no longer see any impact of this
 feature on their Cumulative Layout Shift scores, resulting in a decrease in
 their scores.
 
+### Ignore layout shift when visibility:hidden becomes visible
+
+Sites using visibility:hidden to hide layout changes may see a decrease in
+their Cumulative Layout Shift scores.
+
 ## When were users affected?
 
 Chrome 88 is currently scheduled to be released the week of January 19, 2021.

docs/speed/metrics_changelog/2020_12_cls.md

@@ -2,15 +2,6 @@
 
 ## Changes in Chrome 89
 
-### Ignore layout shift when visibility:hidden becomes visible
-
-We have been always ignoring layout shifts when the element has
-visibility:hidden. However before Chrome 89, if the element having
-visibility:hidden became visible and shift at the same time, we reported layout
-shift. Now we also consider the previous visibility and ignore layout shift in
-the case.
-[Source code for this change](https://chromium-review.googlesource.com/c/chromium/src/+/2591367)
-
 ### Ignore layout shift under opacity:0
 
 [Source code for this change](https://chromium-review.googlesource.com/c/chromium/src/+/2591907)
@@ -27,11 +18,6 @@ are ignored.
 All of these changes only affect sites with specific types of content. Here are
 the specifics for each change:
 
-### Ignore layout shift when visibility:hidden becomes visible
-
-Sites using visibility:hidden to hide layout changes may see a decrease in
-their Cumulative Layout Shift scores.
-
 ### Ignore layout shift under opacity:0
 
 Sites using opacity:0 to hide layout changes should see a decrease in their

docs/speed/metrics_changelog/cls.md

@@ -3,13 +3,13 @@
 This is a list of changes to [Cumulative Layout Shift](https://web.dev/cls).
 
 * Chrome 89
-  * Metric definition improvement: [Ignore layout shift when visibility:hidden becomes visible](2020_12_cls.md)
   * Metric definition improvement: [Ignore layout shift under opacity:0](2020_12_cls.md)
   * Metric definition improvement: [Clip layout shift rect by visual viewport](2020_12_cls.md)
 * Chrome 88
   * Metric definition improvement: [Cumulative layout shift properly detects shifts of fixed position elements](2020_11_cls.md)
   * Metric definition improvement: [Cumulative layout shift properly detects shifts of descendents of a sticky element](2020_11_cls.md)
   * Metric definition improvement: [no penalty for content-visibility: auto content](2020_11_cls.md)
+  * Metric definition improvement: [Ignore layout shift when visibility:hidden becomes visible](2020_11_cls.md)
 * Chrome 87
   * Metric definition improvement: [Fix problem in Cumulative Layout shift calculation of impact region](2020_10_cls_2.md)
   * Metric definition improvement: [Cumulative Layout Shift properly handles clipping of elements styled contain:paint](2020_10_cls_2.md)