--- a/.eslintignore
+++ b/.eslintignore
@@ -126,17 +126,17 @@ devtools/client/webconsole/hudservice.js
 devtools/client/webconsole/webconsole-connection-proxy.js
 devtools/client/webconsole/webconsole.js
 devtools/client/webide/**
 !devtools/client/webide/components/webideCli.js
 devtools/server/tests/browser/storage-*.html
 !devtools/server/tests/browser/storage-unsecured-iframe.html
 devtools/server/tests/browser/stylesheets-nested-iframes.html
 devtools/server/tests/unit/xpcshell_debugging_script.js
-devtools/shared/platform/content/test/test_clipboard.html
+devtools/client/shared/webpack/shims/test/test_clipboard.html
 devtools/shared/qrcode/tests/mochitest/test_decode.html
 devtools/shared/tests/mochitest/*.html
 devtools/shared/webconsole/test/test_*.html
 
 # Ignore devtools preferences files
 devtools/client/preferences/**
 devtools/shim/devtools-startup-prefs.js
 

--- a/devtools/client/inspector/webpack.config.js
+++ b/devtools/client/inspector/webpack.config.js
@@ -94,17 +94,20 @@ module.exports = envConfig => {
         "devtools/client/jsonview/main":
           path.join(__dirname, "./webpack/jsonview-sham.js"),
         "devtools/client/sourceeditor/editor":
           path.join(__dirname, "./webpack/editor-sham.js"),
         "devtools/client/locales": path.join(__dirname, "../locales/en-US"),
         "devtools/shared/DevToolsUtils":
           path.join(__dirname, "./webpack/devtools-utils-sham.js"),
         "devtools/shared/locales": path.join(__dirname, "../../shared/locales/en-US"),
-        "devtools/shared/platform": path.join(__dirname, "../../shared/platform/content"),
+        "devtools/shared/platform/clipboard": path.join(__dirname,
+          "../../client/shared/webpack/shims/platform-clipboard-stub"),
+        "devtools/shared/platform/stack": path.join(__dirname,
+          "../../client/shared/webpack/shims/platform-clipboard-stub"),
         "devtools": path.join(__dirname, "../../"),
         "gcli": path.join(__dirname, "../../shared/gcli/source/lib/gcli"),
         "method": path.join(__dirname, "../../../addon-sdk/source/lib/method"),
         "modules/libpref/init/all":
           path.join(__dirname, "../../../modules/libpref/init/all.js"),
         "devtools/shared/generate-uuid":
           path.join(__dirname, "./webpack/uuid-sham.js"),
         "sdk": path.join(__dirname, "../../../addon-sdk/source/lib/sdk"),

--- a/devtools/client/netmonitor/webpack.config.js
+++ b/devtools/client/netmonitor/webpack.config.js
@@ -82,17 +82,17 @@ let webpackConfig = {
       "devtools/client/shared/vendor/redux": "redux",
       "devtools/client/shared/vendor/reselect": "reselect",
       "devtools/client/shared/vendor/jszip": "jszip",
 
       "devtools/client/sourceeditor/editor": "devtools-source-editor/src/source-editor",
 
       "devtools/shared/old-event-emitter": "devtools-modules/src/utils/event-emitter",
       "devtools/shared/fronts/timeline": path.join(__dirname, "../../client/shared/webpack/shims/fronts-timeline-shim"),
-      "devtools/shared/platform/clipboard": path.join(__dirname, "../../shared/platform/content/clipboard"),
+      "devtools/shared/platform/clipboard": path.join(__dirname, "../../client/shared/webpack/shims/platform-clipboard-stub"),
 
       // Locales need to be explicitly mapped to the en-US subfolder
       "devtools/client/locales": path.join(__dirname, "../../client/locales/en-US"),
       "devtools/shared/locales": path.join(__dirname, "../../shared/locales/en-US"),
       "devtools/shim/locales": path.join(__dirname, "../../shared/locales/en-US"),
       "toolkit/locales": path.join(__dirname, "../../../toolkit/locales/en-US"),
 
       // Unless a path explicitly needs to be rewritten or shimmed, all devtools paths can

--- a/devtools/client/shared/moz.build
+++ b/devtools/client/shared/moz.build
@@ -7,16 +7,17 @@
 BROWSER_CHROME_MANIFESTS += ['test/browser.ini']
 XPCSHELL_TESTS_MANIFESTS += ['test/unit/xpcshell.ini']
 
 DIRS += [
     'components',
     'redux',
     'source-map',
     'vendor',
+    'webpack',
     'widgets',
 ]
 
 DevToolsModules(
     'AppCacheUtils.jsm',
     'autocomplete-popup.js',
     'browser-loader.js',
     'css-angle.js',

new file mode 100644
--- /dev/null
+++ b/devtools/client/shared/webpack/moz.build
@@ -0,0 +1,9 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+DIRS += [
+    'shims',
+]

rename from devtools/shared/platform/content/.eslintrc.js
rename to devtools/client/shared/webpack/shims/.eslintrc.js
--- a/devtools/shared/platform/content/.eslintrc.js
+++ b/devtools/client/shared/webpack/shims/.eslintrc.js
@@ -1,12 +1,12 @@
 "use strict";
 
 module.exports = {
   // Extend from the devtools eslintrc.
-  "extends": "../../../.eslintrc.js",
+  "extends": "../../../../.eslintrc.js",
 
   "rules": {
     /* eslint-disable max-len */
     // All code in this directory must be content-clean.
     "mozilla/reject-some-requires": ["error", "^(chrome|chrome:.*|resource:.*|devtools/server/.*|.*\\.jsm|devtools/shared/platform/(chome|content)/.*)$"],
   },
 };

rename from devtools/shared/platform/content/moz.build
rename to devtools/client/shared/webpack/shims/moz.build
--- a/devtools/shared/platform/content/moz.build
+++ b/devtools/client/shared/webpack/shims/moz.build
@@ -1,16 +1,16 @@
 # -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
 # vim: set filetype=python:
 # 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/.
 
 DevToolsModules(
-    'clipboard.js',
-    'stack.js',
+    'platform-clipboard-stub.js',
+    'platform-stack-stub.js',
 )
 
 XPCSHELL_TESTS_MANIFESTS += ['test/xpcshell.ini']
 
 MOCHITEST_MANIFESTS += [
     'test/mochitest.ini',
 ]

rename from devtools/shared/platform/content/clipboard.js
rename to devtools/client/shared/webpack/shims/platform-clipboard-stub.js

rename from devtools/shared/platform/content/stack.js
rename to devtools/client/shared/webpack/shims/platform-stack-stub.js

rename from devtools/shared/platform/content/test/.eslintrc.js
rename to devtools/client/shared/webpack/shims/test/.eslintrc.js
--- a/devtools/shared/platform/content/test/.eslintrc.js
+++ b/devtools/client/shared/webpack/shims/test/.eslintrc.js
@@ -1,6 +1,6 @@
 "use strict";
 
 module.exports = {
   // Extend from the common devtools xpcshell eslintrc config.
-  "extends": "../../../../.eslintrc.xpcshell.js"
+  "extends": "../../../../../.eslintrc.xpcshell.js"
 };

rename from devtools/shared/platform/content/test/mochitest.ini
rename to devtools/client/shared/webpack/shims/test/mochitest.ini

rename from devtools/shared/platform/content/test/test_clipboard.html
rename to devtools/client/shared/webpack/shims/test/test_clipboard.html
--- a/devtools/shared/platform/content/test/test_clipboard.html
+++ b/devtools/client/shared/webpack/shims/test/test_clipboard.html
@@ -34,17 +34,17 @@ async function pre_do_tests() {
       ["security.all_resource_uri_content_accessible", true]
     ]
   });
 
   // Load script.
   await (() => new Promise((resolve) => {
     var script = document.createElement("script");
     script.onload = resolve;
-    script.src = "resource://devtools/shared/platform/content/clipboard.js";
+    script.src = "resource://devtools/client/shared/webpack/shims/platform-clipboard-stub.js";
     document.head.appendChild(script);
   }))();
 
   do_tests();
 }
 
 function do_tests() {
   let elt = document.querySelector("#key");

rename from devtools/shared/platform/content/test/test_stack.js
rename to devtools/client/shared/webpack/shims/test/test_stack.js
--- a/devtools/shared/platform/content/test/test_stack.js
+++ b/devtools/client/shared/webpack/shims/test/test_stack.js
@@ -4,24 +4,21 @@
 // There isn't really very much about the content stack.js that we can
 // test, but we'll do what we can.
 
 "use strict";
 
 var Cu = Components.utils;
 const {require} = Cu.import("resource://devtools/shared/Loader.jsm", {});
 
-// Make sure to explicitly require the content version of this module.
-// We have to use the ".." trick due to the way the loader remaps
-// devtools/shared/platform.
 const {
   callFunctionWithAsyncStack,
   getStack,
   describeNthCaller
-} = require("devtools/shared/platform/../content/stack");
+} = require("devtools/client/shared/webpack/shims/platform-stack-stub");
 
 function f3() {
   return describeNthCaller(2);
 }
 
 function f2() {
   return f3();
 }

rename from devtools/shared/platform/content/test/xpcshell.ini
rename to devtools/client/shared/webpack/shims/test/xpcshell.ini

--- a/devtools/client/webconsole/webpack.config.js
+++ b/devtools/client/webconsole/webpack.config.js
@@ -85,18 +85,18 @@ webpackConfig.resolve = {
     "devtools/client/framework/menu": "devtools-modules/src/menu",
     "devtools/client/sourceeditor/editor": "devtools-source-editor/src/source-editor",
 
     "devtools/client/shared/zoom-keys": "devtools-modules/src/zoom-keys",
 
     "devtools/shared/fronts/timeline": path.join(__dirname, "../../client/shared/webpack/shims/fronts-timeline-shim"),
     "devtools/shared/old-event-emitter": "devtools-modules/src/utils/event-emitter",
     "devtools/shared/client/main": path.join(__dirname, "new-console-output/test/fixtures/ObjectClient"),
-    "devtools/shared/platform/clipboard": path.join(__dirname, "../../shared/platform/content/clipboard"),
-    "devtools/shared/platform/stack": path.join(__dirname, "../../shared/platform/content/stack"),
+    "devtools/shared/platform/clipboard": path.join(__dirname, "../../client/shared/webpack/shims/platform-clipboard-stub"),
+    "devtools/shared/platform/stack": path.join(__dirname, "../../client/shared/webpack/shims/platform-stack-stub"),
 
     // Locales need to be explicitly mapped to the en-US subfolder
     "toolkit/locales": path.join(__dirname, "../../../toolkit/locales/en-US"),
     "devtools/client/locales": path.join(__dirname, "../../client/locales/en-US"),
     "devtools/shared/locales": path.join(__dirname, "../../shared/locales/en-US"),
     "devtools/shim/locales": path.join(__dirname, "../../shared/locales/en-US"),
 
     // Unless a path explicitly needs to be rewritten or shimmed, all devtools paths can

--- a/devtools/shared/Loader.jsm
+++ b/devtools/shared/Loader.jsm
@@ -25,23 +25,16 @@ this.EXPORTED_SYMBOLS = ["DevToolsLoader
  * Used when the tools should be loaded from the Firefox package itself.
  * This is the default case.
  */
 function BuiltinProvider() {}
 BuiltinProvider.prototype = {
   load: function () {
     const paths = {
       // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
-      // Modules here are intended to have one implementation for
-      // chrome, and a separate implementation for content.  Here we
-      // map the directory to the chrome subdirectory, but the content
-      // loader will map to the content subdirectory.  See the
-      // README.md in devtools/shared/platform.
-      "devtools/shared/platform": "resource://devtools/shared/platform/chrome",
-      // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
       "devtools": "resource://devtools",
       // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
       "gcli": "resource://devtools/shared/gcli/source/lib/gcli",
       // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
       "acorn": "resource://devtools/shared/acorn",
       // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
       "acorn/util/walk": "resource://devtools/shared/acorn/walk.js",
       // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠

deleted file mode 100644
--- a/devtools/shared/platform/README.md
+++ /dev/null
@@ -1,13 +0,0 @@
-This directory is treated specially by the loaders.
-
-In particular, when running in chrome, a resource like
-"devtools/shared/platform/mumble" will be found in the chrome
-subdirectory; and when running in content, it will be found in the
-content subdirectory.
-
-Outside of tests, it's not ok to require a specific version of a file;
-and there is an eslint test to check for that.  That is,
-require("devtools/shared/platform/client/mumble") is an error.
-
-When adding a new file, you must add two copies, one to chrome and one
-to content.  Otherwise, one case or the other will fail to work.

deleted file mode 100644
--- a/devtools/shared/platform/chrome/moz.build
+++ /dev/null
@@ -1,10 +0,0 @@
-# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
-# vim: set filetype=python:
-# 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/.
-
-DevToolsModules(
-    'clipboard.js',
-    'stack.js',
-)

rename from devtools/shared/platform/chrome/clipboard.js
rename to devtools/shared/platform/clipboard.js

--- a/devtools/shared/platform/moz.build
+++ b/devtools/shared/platform/moz.build
@@ -1,10 +1,10 @@
 # -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
 # vim: set filetype=python:
 # 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/.
 
-DIRS += [
-    'chrome',
-    'content',
-]
+DevToolsModules(
+    'clipboard.js',
+    'stack.js',
+)

rename from devtools/shared/platform/chrome/stack.js
rename to devtools/shared/platform/stack.js

--- a/devtools/shared/worker/loader.js
+++ b/devtools/shared/worker/loader.js
@@ -573,23 +573,16 @@ this.worker = new WorkerDebuggerLoader({
   modules: {
     "Debugger": Debugger,
     "Services": Object.create(null),
     "chrome": chrome,
     "xpcInspector": xpcInspector
   },
   paths: {
     // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
-    // Modules here are intended to have one implementation for
-    // chrome, and a separate implementation for content.  Here we
-    // map the directory to the chrome subdirectory, but the content
-    // loader will map to the content subdirectory.  See the
-    // README.md in devtools/shared/platform.
-    "devtools/shared/platform": "resource://devtools/shared/platform/chrome",
-    // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
     "devtools": "resource://devtools",
     // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
     "promise": "resource://gre/modules/Promise-backend.js",
     // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
     "source-map": "resource://devtools/shared/sourcemap/source-map.js",
     // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
     "xpcshell-test": "resource://test"
     // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠