--- a/devtools/client/memory/components/tree-map/canvas-utils.js
+++ b/devtools/client/memory/components/tree-map/canvas-utils.js
@@ -10,17 +10,17 @@
  * Create 2 canvases and contexts for drawing onto, 1 main canvas, and 1 zoom
  * canvas. The main canvas dimensions match the parent div, but the CSS can be
  * transformed to be zoomed and dragged around (potentially creating a blurry
  * canvas once zoomed in). The zoom canvas is a zoomed in section that matches
  * the parent div's dimensions and is kept in place through CSS. A zoomed in
  * view of the visualization is drawn onto this canvas, providing a crisp zoomed
  * in view of the tree map.
  */
-const { debounce } = require("sdk/lang/functional");
+const { debounce } = require("devtools/shared/debounce");
 const EventEmitter = require("devtools/shared/event-emitter");
 
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const FULLSCREEN_STYLE = {
   width: "100%",
   height: "100%",
   position: "absolute",
 };

--- a/devtools/client/memory/components/tree-map/drag-zoom.js
+++ b/devtools/client/memory/components/tree-map/drag-zoom.js
@@ -1,15 +1,15 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
 
-const { debounce } = require("sdk/lang/functional");
+const { debounce } = require("devtools/shared/debounce");
 const { lerp } = require("devtools/client/memory/utils");
 const EventEmitter = require("devtools/shared/event-emitter");
 
 const LERP_SPEED = 0.5;
 const ZOOM_SPEED = 0.01;
 const TRANSLATE_EPSILON = 1;
 const ZOOM_EPSILON = 0.001;
 const LINE_SCROLL_MODE = 1;

--- a/devtools/client/webaudioeditor/views/context.js
+++ b/devtools/client/webaudioeditor/views/context.js
@@ -1,16 +1,16 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 "use strict";
 
 /* import-globals-from ../includes.js */
 
-const { debounce } = require("sdk/lang/functional");
+const { debounce } = require("devtools/shared/debounce");
 const flags = require("devtools/shared/flags");
 
 // Globals for d3 stuff
 // Default properties of the graph on rerender
 const GRAPH_DEFAULTS = {
   translate: [20, 20],
   scale: 1
 };

new file mode 100644
--- /dev/null
+++ b/devtools/shared/debounce.js
@@ -0,0 +1,39 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+/**
+ * From underscore's `_.debounce`
+ * http://underscorejs.org
+ * (c) 2009-2014 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
+ * Underscore may be freely distributed under the MIT license.
+ *
+ * [and in turn extracted from "sdk/lang/functional/concurrent.js"]
+ */
+exports.debounce = function (fn, wait) {
+  let timeout, args, context, timestamp, result;
+
+  let later = function () {
+    let last = Date.now() - timestamp;
+    if (last < wait) {
+      timeout = setTimeout(later, wait - last);
+    } else {
+      timeout = null;
+      result = fn.apply(context, args);
+      context = args = null;
+    }
+  };
+
+  return function (...aArgs) {
+    context = this;
+    args = aArgs;
+    timestamp  = Date.now();
+    if (!timeout) {
+      timeout = setTimeout(later, wait);
+    }
+
+    return result;
+  };
+};

--- a/devtools/shared/moz.build
+++ b/devtools/shared/moz.build
@@ -41,16 +41,17 @@ XPCSHELL_TESTS_MANIFESTS += ['tests/unit
 
 JAR_MANIFESTS += ['jar.mn']
 
 DevToolsModules(
     'async-storage.js',
     'async-utils.js',
     'builtin-modules.js',
     'content-observer.js',
+    'debounce.js',
     'defer.js',
     'deprecated-sync-thenables.js',
     'DevToolsUtils.js',
     'dom-node-constants.js',
     'dom-node-filter-constants.js',
     'event-emitter.js',
     'extend.js',
     'flags.js',