hide exporer arrows improvements (for #35856)

src/vs/workbench/parts/files/browser/media/explorerviewlet.css

@@ -107,7 +107,7 @@
 }
 
 .explorer-folders-view.hide-arrows .monaco-tree-row .content::before {
-	background-image: none;
+	display: none;
 }
 
 .explorer-viewlet .explorer-open-editors .monaco-tree .monaco-tree-row:hover > .content .monaco-action-bar,

src/vs/workbench/services/themes/common/fileIconThemeSchema.ts

@@ -209,6 +209,10 @@ const schema: IJSONSchema = {
 		highContrast: {
 			$ref: '#/definitions/associations',
 			description: nls.localize('schema.highContrast', 'Optional associations for file icons in high contrast color themes.')
+		},
+		hidesExplorerArrows: {
+			type: 'boolean',
+			description: nls.localize('schema.hidesExplorerArrows', 'Configures whether the file explorer\'s arrows should be hidden when this theme is active.')
 		}
 	}
 };

src/vs/workbench/services/themes/electron-browser/fileIconThemeData.ts

@@ -129,7 +129,7 @@ function _loadIconThemeDocument(fileSetPath: string): TPromise<IconThemeDocument
 
 function _processIconThemeDocument(id: string, iconThemeDocumentPath: string, iconThemeDocument: IconThemeDocument): { content: string; hasFileIcons: boolean; hasFolderIcons: boolean; hidesExplorerArrows: boolean; } {
 
-	let result = { content: '', hasFileIcons: false, hasFolderIcons: false, hidesExplorerArrows: false };
+	let result = { content: '', hasFileIcons: false, hasFolderIcons: false, hidesExplorerArrows: iconThemeDocument.hidesExplorerArrows };
 
 	if (!iconThemeDocument.iconDefinitions) {
 		return result;
@@ -251,10 +251,6 @@ function _processIconThemeDocument(id: string, iconThemeDocumentPath: string, ic
 		return result;
 	}
 
-	if (iconThemeDocument.hidesExplorerArrows) {
-		result.hidesExplorerArrows = true;
-	}
-
 	let cssRules: string[] = [];
 
 	let fonts = iconThemeDocument.fonts;