Bug 1569023 - Expose a helper on protocol's Front class to help retrieve the parent front. r=ochameau,yulia

Differential Revision: https://phabricator.services.mozilla.com/D39610

--HG--
extra : moz-landing-system : lando

devtools/client/framework/test/browser.ini

@@ -63,6 +63,7 @@ skip-if = os == 'win' || debug # Bug 1282269, 1448084
 [browser_devtools_api.js]
 [browser_devtools_api_destroy.js]
 [browser_dynamic_tool_enabling.js]
+[browser_front_parentFront.js]
 [browser_ignore_toolbox_network_requests.js]
 [browser_keybindings_01.js]
 [browser_keybindings_02.js]

devtools/client/framework/test/browser_front_parentFront.js

@@ -0,0 +1,42 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test the Front's parentFront attribute returns the correct parent front.
+
+const TEST_URL = `data:text/html;charset=utf-8,<div id="test"></div>`;
+
+add_task(async function() {
+  gBrowser.selectedTab = BrowserTestUtils.addTab(gBrowser);
+
+  const tab = await addTab(TEST_URL);
+  const target = await TargetFactory.forTab(tab);
+  await target.attach();
+
+  const inspectorFront = await target.getFront("inspector");
+  const walker = inspectorFront.walker;
+  const pageStyleFront = await inspectorFront.getPageStyle();
+  const nodeFront = await walker.querySelector(walker.rootNode, "#test");
+
+  is(
+    inspectorFront.parentFront,
+    target,
+    "Got the correct parentFront from the InspectorFront."
+  );
+  is(
+    walker.parentFront,
+    inspectorFront,
+    "Got the correct parentFront from the WalkerFront."
+  );
+  is(
+    pageStyleFront.parentFront,
+    inspectorFront,
+    "Got the correct parentFront from the PageStyleFront."
+  );
+  is(
+    nodeFront.parentFront,
+    walker,
+    "Got the correct parentFront from the NodeFront."
+  );
+});

devtools/client/framework/test/browser_target_get-front.js

@@ -19,6 +19,11 @@ add_task(async function() {
     null,
     "got null from the targetFront attribute for the root"
   );
+  is(
+    client.mainRoot.parentFront,
+    null,
+    "got null from the parentFront attribute for the root"
+  );
 
   info("Test getting a front twice");
   const getAccessibilityFront = await target.getFront("accessibility");
@@ -38,6 +43,16 @@ add_task(async function() {
     target,
     "got the correct targetFront attribute from the front"
   );
+  is(
+    getAccessibilityFront.parentFront,
+    target,
+    "got the correct parentFront attribute from the front"
+  );
+  is(
+    getAccessibilityFront2.parentFront,
+    target,
+    "got the correct parentFront attribute from the front"
+  );
 
   info("Test getting a front on different targets");
   const target1Front = await target.getFront("accessibility");

devtools/shared/fronts/accessibility.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -15,8 +16,8 @@ const {
 const events = require("devtools/shared/event-emitter");
 
 class AccessibleFront extends FrontClassWithSpec(accessibleSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     this.before("audited", this.audited.bind(this));
     this.before("name-change", this.nameChange.bind(this));
@@ -156,8 +157,8 @@ class AccessibleFront extends FrontClassWithSpec(accessibleSpec) {
 }
 
 class AccessibleWalkerFront extends FrontClassWithSpec(accessibleWalkerSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
     this.before("accessible-destroy", this.accessibleDestroy.bind(this));
   }
 
@@ -179,8 +180,8 @@ class AccessibleWalkerFront extends FrontClassWithSpec(accessibleWalkerSpec) {
 }
 
 class AccessibilityFront extends FrontClassWithSpec(accessibilitySpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     this.before("init", this.init.bind(this));
     this.before("shutdown", this.shutdown.bind(this));

devtools/shared/fronts/addon/addons.js

@@ -1,6 +1,7 @@
 /* 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 { addonsSpec } = require("devtools/shared/specs/addon/addons");
@@ -10,8 +11,8 @@ const {
 } = require("devtools/shared/protocol");
 
 class AddonsFront extends FrontClassWithSpec(addonsSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "addonsActor";

devtools/shared/fronts/addon/webextension-inspected-window.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -18,8 +19,8 @@ const {
 class WebExtensionInspectedWindowFront extends FrontClassWithSpec(
   webExtensionInspectedWindowSpec
 ) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "webExtensionInspectedWindowActor";

devtools/shared/fronts/animation.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -13,8 +14,8 @@ const {
 } = require("devtools/shared/specs/animation");
 
 class AnimationPlayerFront extends FrontClassWithSpec(animationPlayerSpec) {
-  constructor(conn, form) {
-    super(conn, form);
+  constructor(conn, targetFront, parentFront) {
+    super(conn, targetFront, parentFront);
 
     this.state = {};
     this.before("changed", this.onChanged.bind(this));
@@ -200,8 +201,8 @@ exports.AnimationPlayerFront = AnimationPlayerFront;
 registerFront(AnimationPlayerFront);
 
 class AnimationsFront extends FrontClassWithSpec(animationsSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "animationsActor";

devtools/shared/fronts/changes.js

@@ -14,8 +14,8 @@ const { changesSpec } = require("devtools/shared/specs/changes");
  * ChangesFront, the front object for the ChangesActor
  */
 class ChangesFront extends FrontClassWithSpec(changesSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "changesActor";

devtools/shared/fronts/css-properties.js

@@ -1,14 +1,14 @@
 /* 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";
 
-loader.lazyRequireGetter(
-  this,
-  "CSS_PROPERTIES_DB",
-  "devtools/shared/css/properties-db",
-  true
-);
+const {
+  FrontClassWithSpec,
+  registerFront,
+} = require("devtools/shared/protocol");
+const { cssPropertiesSpec } = require("devtools/shared/specs/css-properties");
 
 loader.lazyRequireGetter(
   this,
@@ -16,12 +16,18 @@ loader.lazyRequireGetter(
   "devtools/shared/css/color-db",
   true
 );
-
-const {
-  FrontClassWithSpec,
-  registerFront,
-} = require("devtools/shared/protocol");
-const { cssPropertiesSpec } = require("devtools/shared/specs/css-properties");
+loader.lazyRequireGetter(
+  this,
+  "CSS_PROPERTIES_DB",
+  "devtools/shared/css/properties-db",
+  true
+);
+loader.lazyRequireGetter(
+  this,
+  "CSS_TYPES",
+  "devtools/shared/css/constants",
+  true
+);
 
 /**
  * Build up a regular expression that matches a CSS variable token. This is an
@@ -38,23 +44,6 @@ var IS_VARIABLE_TOKEN = new RegExp(
   "i"
 );
 
-loader.lazyRequireGetter(
-  this,
-  "CSS_TYPES",
-  "devtools/shared/css/constants",
-  true
-);
-
-/**
- * Check that this is a CSS variable.
- *
- * @param {String} input
- * @return {Boolean}
- */
-function isCssVariable(input) {
-  return !!input.match(IS_VARIABLE_TOKEN);
-}
-
 var cachedCssProperties = new WeakMap();
 
 /**
@@ -64,28 +53,14 @@ var cachedCssProperties = new WeakMap();
  * properties the current server supports.
  */
 class CssPropertiesFront extends FrontClassWithSpec(cssPropertiesSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront) {
+    super(client, targetFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "cssPropertiesActor";
   }
 }
 
-/**
- * Query the feature supporting status in the featureSet.
- *
- * @param {Hashmap} featureSet the feature set hashmap
- * @param {String} feature the feature name string
- * @return {Boolean} has the feature or not
- */
-function hasFeature(featureSet, feature) {
-  if (feature in featureSet) {
-    return featureSet[feature];
-  }
-  return false;
-}
-
 /**
  * Ask questions to a CSS database. This class does not care how the database
  * gets loaded in, only the questions that you can ask to it.
@@ -209,6 +184,30 @@ CssProperties.prototype = {
   },
 };
 
+/**
+ * Check that this is a CSS variable.
+ *
+ * @param {String} input
+ * @return {Boolean}
+ */
+function isCssVariable(input) {
+  return !!input.match(IS_VARIABLE_TOKEN);
+}
+
+/**
+ * Query the feature supporting status in the featureSet.
+ *
+ * @param {Hashmap} featureSet the feature set hashmap
+ * @param {String} feature the feature name string
+ * @return {Boolean} has the feature or not
+ */
+function hasFeature(featureSet, feature) {
+  if (feature in featureSet) {
+    return featureSet[feature];
+  }
+  return false;
+}
+
 /**
  * Create a CssProperties object with a fully loaded CSS database. The
  * CssProperties interface can be queried synchronously, but the initialization

devtools/shared/fronts/device.js

@@ -1,6 +1,7 @@
 /* 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 { Cu } = require("chrome");
@@ -12,8 +13,8 @@ const {
 const defer = require("devtools/shared/defer");
 
 class DeviceFront extends FrontClassWithSpec(deviceSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "deviceActor";

devtools/shared/fronts/emulation.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -13,8 +14,8 @@ const { emulationSpec } = require("devtools/shared/specs/emulation");
  * The corresponding Front object for the EmulationActor.
  */
 class EmulationFront extends FrontClassWithSpec(emulationSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "emulationActor";

devtools/shared/fronts/framerate.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -13,8 +14,8 @@ const { framerateSpec } = require("devtools/shared/specs/framerate");
  * The corresponding Front object for the FramerateActor.
  */
 class FramerateFront extends FrontClassWithSpec(framerateSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "framerateActor";

devtools/shared/fronts/highlighters.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -14,8 +15,8 @@ const {
 } = require("devtools/shared/specs/highlighters");
 
 class HighlighterFront extends FrontClassWithSpec(highlighterSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     this.isNodeFrontHighlighted = false;
     this.isPicking = false;
@@ -102,8 +103,8 @@ exports.HighlighterFront = HighlighterFront;
 registerFront(HighlighterFront);
 
 class CustomHighlighterFront extends FrontClassWithSpec(customHighlighterSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     this._isShown = false;
   }

devtools/shared/fronts/inspector.js

@@ -1,18 +1,13 @@
 /* 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 Services = require("Services");
+const defer = require("devtools/shared/defer");
 const Telemetry = require("devtools/client/shared/telemetry");
-const telemetry = new Telemetry();
 const { NodePicker } = require("devtools/shared/fronts/inspector/node-picker");
-const TELEMETRY_EYEDROPPER_OPENED = "DEVTOOLS_EYEDROPPER_OPENED_COUNT";
-const TELEMETRY_EYEDROPPER_OPENED_MENU =
-  "DEVTOOLS_MENU_EYEDROPPER_OPENED_COUNT";
-const SHOW_ALL_ANONYMOUS_CONTENT_PREF =
-  "devtools.inspector.showAllAnonymousContent";
-const SHOW_UA_SHADOW_ROOTS_PREF = "devtools.inspector.showUserAgentShadowRoots";
-
 const {
   FrontClassWithSpec,
   types,
@@ -23,8 +18,6 @@ const {
   walkerSpec,
 } = require("devtools/shared/specs/inspector");
 
-const Services = require("Services");
-const defer = require("devtools/shared/defer");
 loader.lazyRequireGetter(
   this,
   "nodeConstants",
@@ -38,6 +31,15 @@ loader.lazyRequireGetter(
 );
 loader.lazyRequireGetter(this, "flags", "devtools/shared/flags");
 
+const TELEMETRY_EYEDROPPER_OPENED = "DEVTOOLS_EYEDROPPER_OPENED_COUNT";
+const TELEMETRY_EYEDROPPER_OPENED_MENU =
+  "DEVTOOLS_MENU_EYEDROPPER_OPENED_COUNT";
+const SHOW_ALL_ANONYMOUS_CONTENT_PREF =
+  "devtools.inspector.showAllAnonymousContent";
+const SHOW_UA_SHADOW_ROOTS_PREF = "devtools.inspector.showUserAgentShadowRoots";
+
+const telemetry = new Telemetry();
+
 /**
  * Client side of the DOM walker.
  */
@@ -52,8 +54,8 @@ class WalkerFront extends FrontClassWithSpec(walkerSpec) {
     });
   }
 
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
     this._createRootNodePromise();
     this._orphaned = new Set();
     this._retainedOrphans = new Set();
@@ -481,8 +483,8 @@ registerFront(WalkerFront);
  * inspector-related actors, including the walker.
  */
 class InspectorFront extends FrontClassWithSpec(inspectorSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     this._client = client;
     this._highlighters = new Map();

devtools/shared/fronts/inspector/node-picker.js

@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 "use strict";
+
 loader.lazyRequireGetter(this, "EventEmitter", "devtools/shared/event-emitter");
 
 /**

devtools/shared/fronts/memory.js

@@ -1,6 +1,7 @@
 /* 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 { memorySpec } = require("devtools/shared/specs/memory");
@@ -22,8 +23,8 @@ loader.lazyRequireGetter(
 );
 
 class MemoryFront extends FrontClassWithSpec(memorySpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
     this._client = client;
     this.heapSnapshotFileActorID = null;
 

devtools/shared/fronts/node.js

@@ -1,17 +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";
 
+const promise = require("promise");
 const {
   FrontClassWithSpec,
   types,
   registerFront,
 } = require("devtools/shared/protocol.js");
-
 const { nodeSpec, nodeListSpec } = require("devtools/shared/specs/node");
-
-const promise = require("promise");
 const { SimpleStringFront } = require("devtools/shared/fronts/string");
 
 loader.lazyRequireGetter(
@@ -114,8 +113,8 @@ class AttributeModificationList {
  * to traverse children.
  */
 class NodeFront extends FrontClassWithSpec(nodeSpec) {
-  constructor(conn, form) {
-    super(conn, form);
+  constructor(conn, targetFront, parentFront) {
+    super(conn, targetFront, parentFront);
     // The parent node
     this._parent = null;
     // The first child of this node.

devtools/shared/fronts/perf.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -10,8 +11,8 @@ const {
 const { perfSpec } = require("devtools/shared/specs/perf");
 
 class PerfFront extends FrontClassWithSpec(perfSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "perfActor";

devtools/shared/fronts/performance-recording.js

@@ -63,8 +63,8 @@ class PerformanceRecordingFront extends FrontClassWithSpec(
     }
   }
 
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
     this._markers = [];
     this._frames = [];
     this._memory = [];

devtools/shared/fronts/performance.js

@@ -1,6 +1,7 @@
 /* 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 { Cu } = require("chrome");
@@ -21,8 +22,8 @@ loader.lazyRequireGetter(
 loader.lazyRequireGetter(this, "getSystemInfo", "devtools/shared/system", true);
 
 class PerformanceFront extends FrontClassWithSpec(performanceSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
     this._queuedRecordings = [];
     this._onRecordingStartedEvent = this._onRecordingStartedEvent.bind(this);
     this.flushQueuedRecordings = this.flushQueuedRecordings.bind(this);

devtools/shared/fronts/preference.js

@@ -1,6 +1,7 @@
 /* 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 { preferenceSpec } = require("devtools/shared/specs/preference");
@@ -10,8 +11,8 @@ const {
 } = require("devtools/shared/protocol");
 
 class PreferenceFront extends FrontClassWithSpec(preferenceSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "preferenceActor";

devtools/shared/fronts/promises.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -13,8 +14,8 @@ const { promisesSpec } = require("devtools/shared/specs/promises");
  * PromisesFront, the front for the PromisesActor.
  */
 class PromisesFront extends FrontClassWithSpec(promisesSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "promisesActor";

devtools/shared/fronts/reflow.js

@@ -19,8 +19,8 @@ const {
  * // now wait for events to come
  */
 class ReflowFront extends FrontClassWithSpec(reflowSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "reflowActor";

devtools/shared/fronts/screenshot.js

@@ -1,6 +1,7 @@
 /* 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 { screenshotSpec } = require("devtools/shared/specs/screenshot");
@@ -11,8 +12,8 @@ const {
 } = require("devtools/shared/protocol");
 
 class ScreenshotFront extends FrontClassWithSpec(screenshotSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "screenshotActor";

devtools/shared/fronts/storage.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -21,8 +22,8 @@ for (const childSpec of Object.values(childSpecs)) {
 }
 
 class StorageFront extends FrontClassWithSpec(storageSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "storageActor";

devtools/shared/fronts/styles.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -23,8 +24,8 @@ loader.lazyRequireGetter(
  * PageStyleFront, the front object for the PageStyleActor
  */
 class PageStyleFront extends FrontClassWithSpec(pageStyleSpec) {
-  constructor(conn) {
-    super(conn);
+  constructor(conn, targetFront, parentFront) {
+    super(conn, targetFront, parentFront);
     this.inspector = this.parent();
   }
 
@@ -84,8 +85,8 @@ registerFront(PageStyleFront);
  * StyleRuleFront, the front for the StyleRule actor.
  */
 class StyleRuleFront extends FrontClassWithSpec(styleRuleSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     this.before("location-changed", this._locationChangedPre.bind(this));
   }

devtools/shared/fronts/stylesheets.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -31,8 +32,8 @@ loader.lazyRequireGetter(
  * Corresponding client-side front for a MediaRuleActor.
  */
 class MediaRuleFront extends FrontClassWithSpec(mediaRuleSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     this._onMatchesChange = this._onMatchesChange.bind(this);
     this.on("matches-change", this._onMatchesChange);
@@ -74,8 +75,8 @@ registerFront(MediaRuleFront);
  * StyleSheetFront is the client-side counterpart to a StyleSheetActor.
  */
 class StyleSheetFront extends FrontClassWithSpec(styleSheetSpec) {
-  constructor(conn, form) {
-    super(conn, form);
+  constructor(conn, targetFront, parentFront) {
+    super(conn, targetFront, parentFront);
 
     this._onPropertyChange = this._onPropertyChange.bind(this);
     this.on("property-change", this._onPropertyChange);
@@ -151,8 +152,8 @@ registerFront(StyleSheetFront);
  * The corresponding Front object for the StyleSheetsActor.
  */
 class StyleSheetsFront extends FrontClassWithSpec(styleSheetsSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     // Attribute name from which to retrieve the actorID out of the target actor's form
     this.formAttributeName = "styleSheetsActor";

devtools/shared/fronts/targets/addon.js

@@ -16,8 +16,8 @@ loader.lazyRequireGetter(
 );
 
 class AddonTargetFront extends FrontClassWithSpec(addonTargetSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     this.client = client;
 

devtools/shared/fronts/thread.js

@@ -34,8 +34,8 @@ loader.lazyRequireGetter(
  *        The actor ID for this thread.
  */
 class ThreadFront extends FrontClassWithSpec(threadSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
     this.client = client;
     this._pauseGrips = {};
     this._threadGrips = {};

devtools/shared/fronts/webconsole.js

@@ -18,15 +18,12 @@ const { webconsoleSpec } = require("devtools/shared/specs/webconsole");
  * A WebConsoleClient is used as a front end for the WebConsoleActor that is
  * created on the server, hiding implementation details.
  *
- * @param object debuggerClient
+ * @param object client
  *        The DebuggerClient instance we live for.
- * @param object response
- *        The response packet received from the "startListeners" request sent to
- *        the WebConsoleActor.
  */
 class WebConsoleFront extends FrontClassWithSpec(webconsoleSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
     this._client = client;
     this.traits = {};
     this._longStrings = {};

devtools/shared/fronts/websocket.js

@@ -1,6 +1,7 @@
 /* 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 {
@@ -14,8 +15,8 @@ const { webSocketSpec } = require("devtools/shared/specs/websocket");
  * created on the server, hiding implementation details.
  */
 class WebSocketFront extends FrontClassWithSpec(webSocketSpec) {
-  constructor(client) {
-    super(client);
+  constructor(client, targetFront, parentFront) {
+    super(client, targetFront, parentFront);
 
     this._onWebSocketOpened = this._onWebSocketOpened.bind(this);
     this._onWebSocketClosed = this._onWebSocketClosed.bind(this);

devtools/shared/protocol/Front.js

@@ -30,19 +30,28 @@ function defer() {
 /**
  * Base class for client-side actor fronts.
  *
- * @param optional conn
- *   Either a DebuggerServerConnection or a DebuggerClient.  Must have
+ * @param [DebuggerClient|null] conn
+ *   The conn must either be DebuggerClient or null. Must have
  *   addActorPool, removeActorPool, and poolFor.
  *   conn can be null if the subclass provides a conn property.
+ * @param [Target|null] target
+ *   If we are instantiating a target-scoped front, this is a reference to the front's
+ *   Target instance, otherwise this is null.
+ * @param [Front|null] parentFront
+ *   The parent front. This is only available if the Front being initialized is a child
+ *   of a parent front.
  * @constructor
  */
 class Front extends Pool {
-  constructor(conn = null) {
+  constructor(conn = null, targetFront = null, parentFront = null) {
     super(conn);
     this.actorID = null;
     // The targetFront attribute represents the debuggable context. Only target-scoped
     // fronts and their children fronts will have the targetFront attribute set.
-    this.targetFront = null;
+    this.targetFront = targetFront;
+    // The parentFront attribute points to its parent front. Only children of
+    // target-scoped fronts will have the parentFront attribute set.
+    this.parentFront = parentFront;
     this._requests = [];
 
     // Front listener functions registered via `onFront` get notified
@@ -75,6 +84,7 @@ class Front extends Pool {
     this.clearEvents();
     this.actorID = null;
     this.targetFront = null;
+    this.parentFront = null;
     this._frontListeners = null;
     this._beforeListeners = null;
   }

devtools/shared/protocol/types.js

@@ -325,15 +325,14 @@ types.addActorType = function(name) {
           lazyLoadFront(name);
         }
 
+        const parentFront = ctx.marshallPool();
+        const targetFront = parentFront.targetFront;
+
         // Use intermediate Class variable to please eslint requiring
         // a capital letter for all constructors.
         const Class = type.frontClass;
-        front = new Class(ctx.conn);
+        front = new Class(ctx.conn, targetFront, parentFront);
         front.actorID = actorID;
-        const parentFront = ctx.marshallPool();
-        // If this is a child of a target-scoped front, propagate the target front to the
-        // child front that it manages.
-        front.targetFront = parentFront.targetFront;
         parentFront.manage(front);
       }
 
@@ -502,16 +501,14 @@ function getFront(client, typeName, form, target = null) {
   const type = types.getType(typeName);
   if (!type) {
     throw new Error(`No spec for front type '${typeName}'.`);
-  }
-  if (!type.frontClass) {
+  } else if (!type.frontClass) {
     lazyLoadFront(typeName);
   }
+
   // Use intermediate Class variable to please eslint requiring
   // a capital letter for all constructors.
   const Class = type.frontClass;
-  const instance = new Class(client);
-  // Set the targetFront for target-scoped fronts.
-  instance.targetFront = target;
+  const instance = new Class(client, target, target);
   const { formAttributeName } = instance;
   if (!formAttributeName) {
     throw new Error(`Can't find the form attribute name for ${typeName}`);