[platform] add LeftRightSearchAwareRenderer combining two renderers and their search strings

platform/platform-api/src/com/intellij/ui/list/LeftRightSearchAwareRenderer.kt

@@ -0,0 +1,24 @@
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.ui.list
+
+import com.intellij.ui.speedSearch.SearchAwareRenderer
+
+/**
+ * A renderer which combines [two renderers][LeftRightRenderer] and combines [search string][getItemSearchString] from both renderers.
+ */
+class LeftRightSearchAwareRenderer<T>(
+  override val mainRenderer: SearchAwareRenderer<T>,
+  override val rightRenderer: SearchAwareRenderer<T>
+) : LeftRightRenderer<T>(),
+    SearchAwareRenderer<T> {
+
+  override fun getItemSearchString(item: T): String? {
+    val main = mainRenderer.getItemSearchString(item)
+    val right = rightRenderer.getItemSearchString(item)
+    return when {
+      main == null -> right
+      right == null -> main
+      else -> "$main $right"
+    }
+  }
+}