Reland "[CSS] Treat viewport-relative units as computationally indepe…

…ndent"

This reverts commit 182115f0e3d61178991b3394e0dd50489df5ea30.

Reason for revert: We are relanding this to prove whether this patch was or was not the cause of the style and layout performance regression.

Original change's description:
> Revert "[CSS] Treat viewport-relative units as computationally independent"
>
> This is a speculative revert in order to either confirm or eliminate it
> as a source for a hard to track down persistent performance regression.
>
> This reverts r679183 (commit 6b846d3689b9038c73d87ecbab61670e91c7e051).
>
> Bug: 993476
> Tbr: pdr@chromium.org
> Change-Id: I37566d32fb0853590e72299fdc0f281c712bf027
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1764195
> Commit-Queue: Emil A Eklund <eae@chromium.org>
> Reviewed-by: Emil A Eklund <eae@chromium.org>
> Reviewed-by: Philip Rogers <pdr@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#689475}

TBR=pdr@chromium.org,eae@chromium.org,xiaochengh@chromium.org,andruud@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 993476
Change-Id: I0292aa653c23ae3b2a751f62ee210626aeb71bbd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1774683
Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#691182}

css/css-properties-values-api/register-property-syntax-parsing.html

@@ -54,6 +54,8 @@
 assert_valid("<length-percentage>", "-54%");
 assert_valid("<length-percentage>", "0");
 assert_valid("<length-percentage>", "calc(-11px + 10.4%)");
+assert_valid("<length>", "10vmin");
+assert_valid("<percentage> | <length>+", "calc(100vh - 10px) 30px");
 
 assert_valid("<number>", "-109");
 assert_valid("<number>", "2.3e4");
@@ -183,14 +185,12 @@
 assert_invalid("<length>", "calc(5px + 10%)");
 assert_invalid("<length>", "calc(5px * 3px / 6px)");
 assert_invalid("<length>", "10em");
-assert_invalid("<length>", "10vmin");
 assert_invalid("<length>", "calc(4px + 3em)");
 assert_invalid("<length>", "calc(4px + calc(8 * 2em))");
 assert_invalid("<length>+", "calc(2ex + 16px)");
 assert_invalid("<length>+", "10px calc(20px + 4rem)");
 assert_invalid("<length>+", "");
 assert_invalid("<length>#", "");
-assert_invalid("<percentage> | <length>+", "calc(100vh - 10px) 30px");
 assert_invalid("<length>", "10px;");
 assert_invalid("<length-percentage>", "calc(2px + 10% + 7ex)");
 assert_invalid("<percentage>", "0");