[MD settings] css for row separator

chrome/browser/resources/settings/settings_shared_css.html

 <link rel="import" href="chrome://resources/cr_elements/shared_style_css.html">
 <link rel="import" href="settings_vars_css.html">
 
 <!-- Common styles for Material Design settings. -->
 <dom-module id="settings-shared">
   <template>
     <style include="cr-shared-style">
       /* Included here so we don't have to include "iron-positioning" in every
        * stylesheet. See crbug.com/498405. */
       [hidden] {
@@ skipping 300 matching lines @@
         align-items: center;
         flex: auto;
       }
 
       .no-outline,
       [scrollable] .no-outline {
         background: none;
         outline: none;
       }
 
-      /* The secondary-action wraps a clickable sub-area of a .settings-box.
-       * An example is the |sign out| button on the People settings.
+      /* TODO(dschuyler): replace with .separator.
+       * The secondary-action wraps a clickable sub-area of a .settings-box.
        * Here is an example with and without a secondary action box:
        *
        *  +-------------------------------------------------------+
        *  | Main action area .settings-box    | .secondary-action |
        *  +-------------------------------------------------------+
        *  | Another setting-box without a secondary-action        |
        *  +-------------------------------------------------------+ */
       :-webkit-any(.settings-box, .list-item) .secondary-action {
         -webkit-border-start: var(--settings-separator-line);
         -webkit-margin-start: 20px;
         -webkit-padding-start: 20px;
         align-items: center;
         display: flex;
         flex-shrink: 0;
         height: 36px;
       }
 
       :-webkit-any(.settings-box, .list-item).two-line .secondary-action {
         height: 46px;
       }
 
       /* Helper for a list frame to automatically avoid the separator line. */
       .vertical-list > *:not(:first-of-type) {
         border-top: var(--settings-separator-line);
       }
 
+      /* The vertical-rule-line is a separator line like a horizontal rule

[Dan Beam, 2017/05/01 15:32:31]

can you update this comment?

[dschuyler, 2017/05/01 19:26:11]

Done.

+       * <hr> tag, but goes the other way.
+       * An example is near the |sign out| button on the People settings. */
+      :-webkit-any(.settings-box, .list-item) .separator {
+        -webkit-border-start: var(--settings-separator-line);
+        -webkit-margin-start: var(--settings-box-row-padding);
+        -webkit-padding-start: var(--settings-box-row-padding);

[Dan Beam, 2017/05/01 15:32:31]

is there a reason we have to use padding instead of margin-end?

[dschuyler, 2017/05/01 19:26:11]

There used to be (when the div had contents), but that no longer applies.

Done.

+        flex-shrink: 0;
+        --settings-separator-gaps: 9px;

[Dan Beam, 2017/05/01 15:32:31]

so wait, does this mean 4.5px on top and bottom? do we want an even number?

[dschuyler, 2017/05/01 19:26:11]

The numbers bettes@ asked for is 45px row with a 36px vertical line. It looks
good in practice because the half px allows for an anit-aliasing tapering of the
tips. I'd question Alan further on it if it looked wrong, but it looks fine imo.

+        height: calc(var(--settings-row-min-height) -
+            var(--settings-separator-gaps));
+      }
+
+      :-webkit-any(.settings-box, .list-item).two-line .separator {
+        height: calc(var(--settings-row-two-line-min-height) -
+            2 * var(--settings-separator-gaps));

[Dan Beam, 2017/05/01 15:32:31]

why is this doubled in this case?

[dschuyler, 2017/05/01 19:26:11]

This is from an aesthetic call by UI (bettes@): on a 64px row the grey line
should be 56px. This could also be done with a separate variable like
--settings-two-line-separator-gaps: 18px.

+      }
+
       .settings-checkbox-spacer {
         -webkit-margin-start: calc(
             var(--checkbox-margin-start) +
             var(--checkbox-size) +
             var(--settings-control-spacing));
       }
 
       .favicon-image {
         background-repeat: no-repeat;
         background-size: contain;
@@ skipping 36 matching lines @@
         transform: rotate(-135deg);
       }
 
       .column-header {
         color: var(--paper-grey-600);
         font-weight: 500;
       }
     </style>
   </template>
 </dom-module>