Remove CSS regions support, keeping a bare minimum to support "region-based" multicol.

Source/devtools/devtools.gypi

Index: Source/devtools/devtools.gypi
diff --git a/Source/devtools/devtools.gypi b/Source/devtools/devtools.gypi
index 4f93bbfe1e02340dd2b9abbc37de8d61b1d95d25..0449c1da44b415107c64c0c4683b98f87c92f852 100644
--- a/Source/devtools/devtools.gypi
+++ b/Source/devtools/devtools.gypi
@@ -205,7 +205,6 @@
             'front_end/buildSystemOnly.js',
             'front_end/cm/cmdevtools.css',
             'front_end/cm/codemirror.css',
-            'front_end/cssNamedFlows.css',
             'front_end/dataGrid.css',
             'front_end/elementsPanel.css',
             'front_end/filter.css',
@@ -236,8 +235,6 @@
             'front_end/layersPanel.css',
         ],
         'devtools_elements_js_files': [
-            'front_end/CSSNamedFlowCollectionsView.js',
-            'front_end/CSSNamedFlowView.js',
             'front_end/DOMSyntaxHighlighter.js',
             'front_end/ElementsTreeOutline.js',
             'front_end/ElementsPanel.js',
@@ -394,7 +391,6 @@
             'front_end/Images/breakpointConditional_2x.png',
             'front_end/Images/checker.png',
             'front_end/Images/cookie.png',
-            'front_end/Images/namedFlowOverflow.png',
             'front_end/Images/database.png',
             'front_end/Images/databaseTable.png',
             'front_end/Images/deleteIcon.png',
@@ -421,9 +417,6 @@
             'front_end/Images/profileIcon.png',
             'front_end/Images/profileSmallIcon.png',
             'front_end/Images/radioDot.png',
-            'front_end/Images/regionEmpty.png',
-            'front_end/Images/regionFit.png',
-            'front_end/Images/regionOverset.png',
             'front_end/Images/resourceCSSIcon.png',
             'front_end/Images/resourceDocumentIcon.png',
             'front_end/Images/resourceDocumentIconSmall.png',