Change cr-input styling for files-ng

This changes the placeholder text color to make it visible with a light
background.

Changes the non-focussed underline color as a temporary fix, this will
be replaced by styling the entire search area with a grey box in a
follow up CL.

Bug: 992823
Change-Id: I5d97ccd700950f995309afd54888ebfb60036a1d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2054655Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741399}

ui/file_manager/file_manager/foreground/css/file_manager.css

@@ -603,18 +603,26 @@ html[dir='rtl'] .dialog-header button.icon-button > files-toggle-ripple {
 
 .dialog-header #search-box cr-input {
   --cr-input-background-color: transparent;
-  --cr-input-border-bottom: 1px solid rgba(255, 255, 255, 0.5);
   --cr-input-border-radius: 0;
   --cr-input-error-display: none;
   --cr-input-padding-end: 20px;
   --cr-input-padding-start: 0;
-  --cr-input-placeholder-color: rgba(255, 255, 255, 0.5);
   display: inline-block;
   transition: width 200ms ease;
   vertical-align: middle;
   width: 0;
 }
 
+.dialog-header:not(.files-ng) #search-box cr-input {
+  --cr-input-border-bottom: 1px solid rgba(255, 255, 255, 50%);
+  --cr-input-placeholder-color: rgba(255, 255, 255, 50%);
+}
+
+.dialog-header.files-ng #search-box cr-input {
+  --cr-input-border-bottom: 1px solid rgba(0, 0, 0, 50%);
+  --cr-input-placeholder-color: rgba(0, 0, 0, 50%);
+}
+
 .dialog-header:not(.files-ng) #search-button > .icon {
   background-image: -webkit-image-set(
       url(../images/files/ui/search_white.png) 1x,