DevTools: shadow editor fields should not shrink

This adds styles to prevent fields in the CSS shadow editor from
shrinking. Bezier and Color swatch popovers are already scroll well
under small window dimensions.

Screenshot: https://imgur.com/a/hpIMe

Bug: 827093
Change-Id: I0ff7d4ca336cf728b79dac02feca4a0d60cff12f
Reviewed-on: https://chromium-review.googlesource.com/986661
Reviewed-by: Andrey Lushnikov <[email protected]>
Commit-Queue: Andrey Lushnikov <[email protected]>
Cr-Original-Commit-Position: refs/heads/master@{#547885}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: dfc1d98ec52ba592b1e47bd6ff9576ac9c94ec7d
diff --git a/front_end/inline_editor/cssShadowEditor.css b/front_end/inline_editor/cssShadowEditor.css
index 712146b..1c849b8 100644
--- a/front_end/inline_editor/cssShadowEditor.css
+++ b/front_end/inline_editor/cssShadowEditor.css
@@ -9,10 +9,15 @@
     padding: 4px 12px 12px 12px;
 }
 
+.shadow-editor-field:last-of-type {
+    margin-bottom: 8px;
+}
+
 .shadow-editor-field {
     height: 24px;
     margin-top: 8px;
     font-size: 12px;
+    flex-shrink: 0;
 }
 
 .shadow-editor-flex-field {