[text-box-trim] Test accumulations

This patch adds a test for when the element to trim has
different `text-box-edge` value from the `text-box-edge` value
of the element that has `text-box-trim`. Discussed and
resolved at:
w3c/csswg-drafts#5426

Bug: 40254880
Change-Id: I5685fbaebddb8c7429b3b041c5fe0f88b982fc3d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5547563
Auto-Submit: Koji Ishii 
Reviewed-by: Kent Tamura 
Commit-Queue: Kent Tamura 
Cr-Commit-Position: refs/heads/main@{#1303166}

Author: kojiishi

css/css-inline/text-box-trim/text-box-trim-accumulation-001.html

@@ -0,0 +1,32 @@
+>
+<title>Test choosing the innermost for `text-box-trim` for requested trim metrictitle>
+<link rel="help" href="https://drafts.csswg.org/css-inline-3/#propdef-text-box-edge">
+<link rel="help" href="https://drafts.csswg.org/css-inline-3/#propdef-text-box-trim">
+<link rel="match" href="text-box-trim-start-001-ref.html?class=text">
+<link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+<style>
+.spacer {
+  block-size: 100px;
+  background: lightgray;
+}
+.target {
+  font-family: Ahem;
+  font-size: 100px;
+  line-height: 2;
+  text-box-trim: start;
+  text-box-edge: leading;
+}
+.inner {
+  text-box-edge: text;
+}
+style>
+<div class="spacer">div>
+<div class="target">
+  
+  <div class="inner">Adiv>
+div>
+<div class="spacer">div>