Add m-esr52 at 52.6.0

5 files changed, 928 insertions, 0 deletions

diff --git a/devtools/client/webaudioeditor/views/automation.js b/devtools/client/webaudioeditor/views/automation.js
new file mode 100644
index 000000000..2fab262bd
--- /dev/null
+++ b/devtools/client/webaudioeditor/views/automation.js
@@ -0,0 +1,159 @@
+/* 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";
+
+/**
+ * Functions handling the audio node inspector UI.
+ */
+
+var AutomationView = {
+
+  /**
+   * Initialization function called when the tool starts up.
+   */
+  initialize: function () {
+    this._buttons = $("#automation-param-toolbar-buttons");
+    this.graph = new LineGraphWidget($("#automation-graph"), { avg: false });
+    this.graph.selectionEnabled = false;
+
+    this._onButtonClick = this._onButtonClick.bind(this);
+    this._onNodeSet = this._onNodeSet.bind(this);
+    this._onResize = this._onResize.bind(this);
+
+    this._buttons.addEventListener("click", this._onButtonClick);
+    window.on(EVENTS.UI_INSPECTOR_RESIZE, this._onResize);
+    window.on(EVENTS.UI_INSPECTOR_NODE_SET, this._onNodeSet);
+  },
+
+  /**
+   * Destruction function called when the tool cleans up.
+   */
+  destroy: function () {
+    this._buttons.removeEventListener("click", this._onButtonClick);
+    window.off(EVENTS.UI_INSPECTOR_RESIZE, this._onResize);
+    window.off(EVENTS.UI_INSPECTOR_NODE_SET, this._onNodeSet);
+  },
+
+  /**
+   * Empties out the props view.
+   */
+  resetUI: function () {
+    this._currentNode = null;
+  },
+
+  /**
+   * On a new node selection, create the Automation panel for
+   * that specific node.
+   */
+  build: Task.async(function* () {
+    let node = this._currentNode;
+
+    let props = yield node.getParams();
+    let params = props.filter(({ flags }) => flags && flags.param);
+
+    this._createParamButtons(params);
+
+    this._selectedParamName = params[0] ? params[0].param : null;
+    this.render();
+  }),
+
+  /**
+   * Renders the graph for specified `paramName`. Called when
+   * the parameter view is changed, or when new param data events
+   * are fired for the currently specified param.
+   */
+  render: Task.async(function* () {
+    let node = this._currentNode;
+    let paramName = this._selectedParamName;
+    // Escape if either node or parameter name does not exist.
+    if (!node || !paramName) {
+      this._setState("no-params");
+      window.emit(EVENTS.UI_AUTOMATION_TAB_RENDERED, null);
+      return;
+    }
+
+    let { values, events } = yield node.getAutomationData(paramName);
+    this._setState(events.length ? "show" : "no-events");
+    yield this.graph.setDataWhenReady(values);
+    window.emit(EVENTS.UI_AUTOMATION_TAB_RENDERED, node.id);
+  }),
+
+  /**
+   * Create the buttons for each AudioParam, that when clicked,
+   * render the graph for that AudioParam.
+   */
+  _createParamButtons: function (params) {
+    this._buttons.innerHTML = "";
+    params.forEach((param, i) => {
+      let button = document.createElement("toolbarbutton");
+      button.setAttribute("class", "devtools-toolbarbutton automation-param-button");
+      button.setAttribute("data-param", param.param);
+      // Set label to the parameter name, should not be L10N'd
+      button.setAttribute("label", param.param);
+
+      // If first button, set to 'selected' for styling
+      if (i === 0) {
+        button.setAttribute("selected", true);
+      }
+
+      this._buttons.appendChild(button);
+    });
+  },
+
+  /**
+   * Internally sets the current audio node and rebuilds appropriate
+   * views.
+   */
+  _setAudioNode: function (node) {
+    this._currentNode = node;
+    if (this._currentNode) {
+      this.build();
+    }
+  },
+
+  /**
+   * Toggles the subviews to display messages whether or not
+   * the audio node has no AudioParams, no automation events, or
+   * shows the graph.
+   */
+  _setState: function (state) {
+    let contentView = $("#automation-content");
+    let emptyView = $("#automation-empty");
+
+    let graphView = $("#automation-graph-container");
+    let noEventsView = $("#automation-no-events");
+
+    contentView.hidden = state === "no-params";
+    emptyView.hidden = state !== "no-params";
+
+    graphView.hidden = state !== "show";
+    noEventsView.hidden = state !== "no-events";
+  },
+
+  /**
+   * Event handlers
+   */
+
+  _onButtonClick: function (e) {
+    Array.forEach($$(".automation-param-button"), $btn => $btn.removeAttribute("selected"));
+    let paramName = e.target.getAttribute("data-param");
+    e.target.setAttribute("selected", true);
+    this._selectedParamName = paramName;
+    this.render();
+  },
+
+  /**
+   * Called when the inspector is resized.
+   */
+  _onResize: function () {
+    this.graph.refresh();
+  },
+
+  /**
+   * Called when the inspector view determines a node is selected.
+   */
+  _onNodeSet: function (_, id) {
+    this._setAudioNode(id != null ? gAudioNodes.get(id) : null);
+  }
+};
diff --git a/devtools/client/webaudioeditor/views/context.js b/devtools/client/webaudioeditor/views/context.js
new file mode 100644
index 000000000..69ecc141e
--- /dev/null
+++ b/devtools/client/webaudioeditor/views/context.js
@@ -0,0 +1,314 @@
+/* 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 flags = require("devtools/shared/flags");
+
+// Globals for d3 stuff
+// Default properties of the graph on rerender
+const GRAPH_DEFAULTS = {
+  translate: [20, 20],
+  scale: 1
+};
+
+// Sizes of SVG arrows in graph
+const ARROW_HEIGHT = 5;
+const ARROW_WIDTH = 8;
+
+// Styles for markers as they cannot be done with CSS.
+const MARKER_STYLING = {
+  light: "#AAA",
+  dark: "#CED3D9"
+};
+Object.defineProperty(this, "MARKER_STYLING", {
+  value: MARKER_STYLING,
+  enumerable: true,
+  writable: false
+});
+
+const GRAPH_DEBOUNCE_TIMER = 100;
+
+// `gAudioNodes` events that should require the graph
+// to redraw
+const GRAPH_REDRAW_EVENTS = ["add", "connect", "disconnect", "remove"];
+
+/**
+ * Functions handling the graph UI.
+ */
+var ContextView = {
+  /**
+   * Initialization function, called when the tool is started.
+   */
+  initialize: function () {
+    this._onGraphClick = this._onGraphClick.bind(this);
+    this._onThemeChange = this._onThemeChange.bind(this);
+    this._onStartContext = this._onStartContext.bind(this);
+    this._onEvent = this._onEvent.bind(this);
+
+    this.draw = debounce(this.draw.bind(this), GRAPH_DEBOUNCE_TIMER);
+    $("#graph-target").addEventListener("click", this._onGraphClick, false);
+
+    window.on(EVENTS.THEME_CHANGE, this._onThemeChange);
+    window.on(EVENTS.START_CONTEXT, this._onStartContext);
+    gAudioNodes.on("*", this._onEvent);
+  },
+
+  /**
+   * Destruction function, called when the tool is closed.
+   */
+  destroy: function () {
+    // If the graph was rendered at all, then the handler
+    // for zooming in will be set. We must remove it to prevent leaks.
+    if (this._zoomBinding) {
+      this._zoomBinding.on("zoom", null);
+    }
+    $("#graph-target").removeEventListener("click", this._onGraphClick, false);
+
+    window.off(EVENTS.THEME_CHANGE, this._onThemeChange);
+    window.off(EVENTS.START_CONTEXT, this._onStartContext);
+    gAudioNodes.off("*", this._onEvent);
+  },
+
+  /**
+   * Called when a page is reloaded and waiting for a "start-context" event
+   * and clears out old content
+   */
+  resetUI: function () {
+    this.clearGraph();
+    this.resetGraphTransform();
+  },
+
+  /**
+   * Clears out the rendered graph, called when resetting the SVG elements to draw again,
+   * or when resetting the entire UI tool
+   */
+  clearGraph: function () {
+    $("#graph-target").innerHTML = "";
+  },
+
+  /**
+   * Moves the graph back to its original scale and translation.
+   */
+  resetGraphTransform: function () {
+    // Only reset if the graph was ever drawn.
+    if (this._zoomBinding) {
+      let { translate, scale } = GRAPH_DEFAULTS;
+      // Must set the `zoomBinding` so the next `zoom` event is in sync with
+      // where the graph is visually (set by the `transform` attribute).
+      this._zoomBinding.scale(scale);
+      this._zoomBinding.translate(translate);
+      d3.select("#graph-target")
+        .attr("transform", "translate(" + translate + ") scale(" + scale + ")");
+    }
+  },
+
+  getCurrentScale: function () {
+    return this._zoomBinding ? this._zoomBinding.scale() : null;
+  },
+
+  getCurrentTranslation: function () {
+    return this._zoomBinding ? this._zoomBinding.translate() : null;
+  },
+
+  /**
+   * Makes the corresponding graph node appear "focused", removing
+   * focused styles from all other nodes. If no `actorID` specified,
+   * make all nodes appear unselected.
+   */
+  focusNode: function (actorID) {
+    // Remove class "selected" from all nodes
+    Array.forEach($$(".nodes > g"), $node => $node.classList.remove("selected"));
+    // Add to "selected"
+    if (actorID) {
+      this._getNodeByID(actorID).classList.add("selected");
+    }
+  },
+
+  /**
+   * Takes an actorID and returns the corresponding DOM SVG element in the graph
+   */
+  _getNodeByID: function (actorID) {
+    return $(".nodes > g[data-id='" + actorID + "']");
+  },
+
+  /**
+   * Sets the appropriate class on an SVG node when its bypass
+   * status is toggled.
+   */
+  _bypassNode: function (node, enabled) {
+    let el = this._getNodeByID(node.id);
+    el.classList[enabled ? "add" : "remove"]("bypassed");
+  },
+
+  /**
+   * This method renders the nodes currently available in `gAudioNodes` and is
+   * throttled to be called at most every `GRAPH_DEBOUNCE_TIMER` milliseconds.
+   * It's called whenever the audio context routing changes, after being debounced.
+   */
+  draw: function () {
+    // Clear out previous SVG information
+    this.clearGraph();
+
+    let graph = new dagreD3.Digraph();
+    let renderer = new dagreD3.Renderer();
+    gAudioNodes.populateGraph(graph);
+
+    // Post-render manipulation of the nodes
+    let oldDrawNodes = renderer.drawNodes();
+    renderer.drawNodes(function (graph, root) {
+      let svgNodes = oldDrawNodes(graph, root);
+      svgNodes.each(function (n) {
+        let node = graph.node(n);
+        let classString = "audionode type-" + node.type + (node.bypassed ? " bypassed" : "");
+        this.setAttribute("class", classString);
+        this.setAttribute("data-id", node.id);
+        this.setAttribute("data-type", node.type);
+      });
+      return svgNodes;
+    });
+
+    // Post-render manipulation of edges
+    let oldDrawEdgePaths = renderer.drawEdgePaths();
+    let defaultClasses = "edgePath enter";
+
+    renderer.drawEdgePaths(function (graph, root) {
+      let svgEdges = oldDrawEdgePaths(graph, root);
+      svgEdges.each(function (e) {
+        let edge = graph.edge(e);
+
+        // We have to manually specify the default classes on the edges
+        // as to not overwrite them
+        let edgeClass = defaultClasses + (edge.param ? (" param-connection " + edge.param) : "");
+
+        this.setAttribute("data-source", edge.source);
+        this.setAttribute("data-target", edge.target);
+        this.setAttribute("data-param", edge.param ? edge.param : null);
+        this.setAttribute("class", edgeClass);
+      });
+
+      return svgEdges;
+    });
+
+    // Override Dagre-d3's post render function by passing in our own.
+    // This way we can leave styles out of it.
+    renderer.postRender((graph, root) => {
+      // We have to manually set the marker styling since we cannot
+      // do this currently with CSS, although it is in spec for SVG2
+      // https://svgwg.org/svg2-draft/painting.html#VertexMarkerProperties
+      // For now, manually set it on creation, and the `_onThemeChange`
+      // function will fire when the devtools theme changes to update the
+      // styling manually.
+      let theme = Services.prefs.getCharPref("devtools.theme");
+      let markerColor = MARKER_STYLING[theme];
+      if (graph.isDirected() && root.select("#arrowhead").empty()) {
+        root
+          .append("svg:defs")
+          .append("svg:marker")
+          .attr("id", "arrowhead")
+          .attr("viewBox", "0 0 10 10")
+          .attr("refX", ARROW_WIDTH)
+          .attr("refY", ARROW_HEIGHT)
+          .attr("markerUnits", "strokewidth")
+          .attr("markerWidth", ARROW_WIDTH)
+          .attr("markerHeight", ARROW_HEIGHT)
+          .attr("orient", "auto")
+          .attr("style", "fill: " + markerColor)
+          .append("svg:path")
+          .attr("d", "M 0 0 L 10 5 L 0 10 z");
+      }
+
+      // Reselect the previously selected audio node
+      let currentNode = InspectorView.getCurrentAudioNode();
+      if (currentNode) {
+        this.focusNode(currentNode.id);
+      }
+
+      // Fire an event upon completed rendering, with extra information
+      // if in testing mode only.
+      let info = {};
+      if (flags.testing) {
+        info = gAudioNodes.getInfo();
+      }
+      window.emit(EVENTS.UI_GRAPH_RENDERED, info.nodes, info.edges, info.paramEdges);
+    });
+
+    let layout = dagreD3.layout().rankDir("LR");
+    renderer.layout(layout).run(graph, d3.select("#graph-target"));
+
+    // Handle the sliding and zooming of the graph,
+    // store as `this._zoomBinding` so we can unbind during destruction
+    if (!this._zoomBinding) {
+      this._zoomBinding = d3.behavior.zoom().on("zoom", function () {
+        var ev = d3.event;
+        d3.select("#graph-target")
+          .attr("transform", "translate(" + ev.translate + ") scale(" + ev.scale + ")");
+      });
+      d3.select("svg").call(this._zoomBinding);
+
+      // Set initial translation and scale -- this puts D3's awareness of
+      // the graph in sync with what the user sees originally.
+      this.resetGraphTransform();
+    }
+  },
+
+  /**
+   * Event handlers
+   */
+
+  /**
+   * Called once "start-context" is fired, indicating that there is an audio
+   * context being created to view so render the graph.
+   */
+  _onStartContext: function () {
+    this.draw();
+  },
+
+  /**
+   * Called when `gAudioNodes` fires an event -- most events (listed
+   * in GRAPH_REDRAW_EVENTS) qualify as a redraw event.
+   */
+  _onEvent: function (eventName, ...args) {
+    // If bypassing, just toggle the class on the SVG node
+    // rather than rerendering everything
+    if (eventName === "bypass") {
+      this._bypassNode.apply(this, args);
+    }
+    if (~GRAPH_REDRAW_EVENTS.indexOf(eventName)) {
+      this.draw();
+    }
+  },
+
+  /**
+   * Fired when the devtools theme changes.
+   */
+  _onThemeChange: function (eventName, theme) {
+    let markerColor = MARKER_STYLING[theme];
+    let marker = $("#arrowhead");
+    if (marker) {
+      marker.setAttribute("style", "fill: " + markerColor);
+    }
+  },
+
+  /**
+   * Fired when a click occurs in the graph.
+   *
+   * @param Event e
+   *        Click event.
+   */
+  _onGraphClick: function (e) {
+    let node = findGraphNodeParent(e.target);
+    // If node not found (clicking outside of an audio node in the graph),
+    // then ignore this event
+    if (!node)
+      return;
+
+    let id = node.getAttribute("data-id");
+
+    this.focusNode(id);
+    window.emit(EVENTS.UI_SELECT_NODE, id);
+  }
+};
diff --git a/devtools/client/webaudioeditor/views/inspector.js b/devtools/client/webaudioeditor/views/inspector.js
new file mode 100644
index 000000000..1f50bb137
--- /dev/null
+++ b/devtools/client/webaudioeditor/views/inspector.js
@@ -0,0 +1,189 @@
+/* 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 MIN_INSPECTOR_WIDTH = 300;
+
+// Strings for rendering
+const EXPAND_INSPECTOR_STRING = L10N.getStr("expandInspector");
+const COLLAPSE_INSPECTOR_STRING = L10N.getStr("collapseInspector");
+
+/**
+ * Functions handling the audio node inspector UI.
+ */
+
+var InspectorView = {
+  _currentNode: null,
+
+  // Set up config for view toggling
+  _collapseString: COLLAPSE_INSPECTOR_STRING,
+  _expandString: EXPAND_INSPECTOR_STRING,
+  _toggleEvent: EVENTS.UI_INSPECTOR_TOGGLED,
+  _animated: true,
+  _delayed: true,
+
+  /**
+   * Initialization function called when the tool starts up.
+   */
+  initialize: function () {
+    // Set up view controller
+    this.el = $("#web-audio-inspector");
+    this.splitter = $("#inspector-splitter");
+    this.el.setAttribute("width", Services.prefs.getIntPref("devtools.webaudioeditor.inspectorWidth"));
+    this.button = $("#inspector-pane-toggle");
+    mixin(this, ToggleMixin);
+    this.bindToggle();
+
+    // Hide inspector view on startup
+    this.hideImmediately();
+
+    this._onNodeSelect = this._onNodeSelect.bind(this);
+    this._onDestroyNode = this._onDestroyNode.bind(this);
+    this._onResize = this._onResize.bind(this);
+    this._onCommandClick = this._onCommandClick.bind(this);
+
+    this.splitter.addEventListener("mouseup", this._onResize);
+    for (let $el of $$("#audio-node-toolbar toolbarbutton")) {
+      $el.addEventListener("command", this._onCommandClick);
+    }
+    window.on(EVENTS.UI_SELECT_NODE, this._onNodeSelect);
+    gAudioNodes.on("remove", this._onDestroyNode);
+  },
+
+  /**
+   * Destruction function called when the tool cleans up.
+   */
+  destroy: function () {
+    this.unbindToggle();
+    this.splitter.removeEventListener("mouseup", this._onResize);
+
+    $("#audio-node-toolbar toolbarbutton").removeEventListener("command", this._onCommandClick);
+    for (let $el of $$("#audio-node-toolbar toolbarbutton")) {
+      $el.removeEventListener("command", this._onCommandClick);
+    }
+    window.off(EVENTS.UI_SELECT_NODE, this._onNodeSelect);
+    gAudioNodes.off("remove", this._onDestroyNode);
+
+    this.el = null;
+    this.button = null;
+    this.splitter = null;
+  },
+
+  /**
+   * Takes a AudioNodeView `node` and sets it as the current
+   * node and scaffolds the inspector view based off of the new node.
+   */
+  setCurrentAudioNode: Task.async(function* (node) {
+    this._currentNode = node || null;
+
+    // If no node selected, set the inspector back to "no AudioNode selected"
+    // view.
+    if (!node) {
+      $("#web-audio-editor-details-pane-empty").removeAttribute("hidden");
+      $("#web-audio-editor-tabs").setAttribute("hidden", "true");
+      window.emit(EVENTS.UI_INSPECTOR_NODE_SET, null);
+    }
+    // Otherwise load up the tabs view and hide the empty placeholder
+    else {
+      $("#web-audio-editor-details-pane-empty").setAttribute("hidden", "true");
+      $("#web-audio-editor-tabs").removeAttribute("hidden");
+      this._buildToolbar();
+      window.emit(EVENTS.UI_INSPECTOR_NODE_SET, this._currentNode.id);
+    }
+  }),
+
+  /**
+   * Returns the current AudioNodeView.
+   */
+  getCurrentAudioNode: function () {
+    return this._currentNode;
+  },
+
+  /**
+   * Empties out the props view.
+   */
+  resetUI: function () {
+    // Set current node to empty to load empty view
+    this.setCurrentAudioNode();
+
+    // Reset AudioNode inspector and hide
+    this.hideImmediately();
+  },
+
+  _buildToolbar: function () {
+    let node = this.getCurrentAudioNode();
+
+    let bypassable = node.bypassable;
+    let bypassed = node.isBypassed();
+    let button = $("#audio-node-toolbar .bypass");
+
+    if (!bypassable) {
+      button.setAttribute("disabled", true);
+    } else {
+      button.removeAttribute("disabled");
+    }
+
+    if (!bypassable || bypassed) {
+      button.removeAttribute("checked");
+    } else {
+      button.setAttribute("checked", true);
+    }
+  },
+
+  /**
+   * Event handlers
+   */
+
+  /**
+   * Called on EVENTS.UI_SELECT_NODE, and takes an actorID `id`
+   * and calls `setCurrentAudioNode` to scaffold the inspector view.
+   */
+  _onNodeSelect: function (_, id) {
+    this.setCurrentAudioNode(gAudioNodes.get(id));
+
+    // Ensure inspector is visible when selecting a new node
+    this.show();
+  },
+
+  _onResize: function () {
+    if (this.el.getAttribute("width") < MIN_INSPECTOR_WIDTH) {
+      this.el.setAttribute("width", MIN_INSPECTOR_WIDTH);
+    }
+    Services.prefs.setIntPref("devtools.webaudioeditor.inspectorWidth", this.el.getAttribute("width"));
+    window.emit(EVENTS.UI_INSPECTOR_RESIZE);
+  },
+
+  /**
+   * Called when `DESTROY_NODE` is fired to remove the node from props view if
+   * it's currently selected.
+   */
+  _onDestroyNode: function (node) {
+    if (this._currentNode && this._currentNode.id === node.id) {
+      this.setCurrentAudioNode(null);
+    }
+  },
+
+  _onCommandClick: function (e) {
+    let node = this.getCurrentAudioNode();
+    let button = e.target;
+    let command = button.getAttribute("data-command");
+    let checked = button.getAttribute("checked");
+
+    if (button.getAttribute("disabled")) {
+      return;
+    }
+
+    if (command === "bypass") {
+      if (checked) {
+        button.removeAttribute("checked");
+        node.bypass(true);
+      } else {
+        button.setAttribute("checked", true);
+        node.bypass(false);
+      }
+    }
+  }
+};
diff --git a/devtools/client/webaudioeditor/views/properties.js b/devtools/client/webaudioeditor/views/properties.js
new file mode 100644
index 000000000..efd691e5a
--- /dev/null
+++ b/devtools/client/webaudioeditor/views/properties.js
@@ -0,0 +1,163 @@
+/* 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 { VariablesView } = require("resource://devtools/client/shared/widgets/VariablesView.jsm");
+
+const GENERIC_VARIABLES_VIEW_SETTINGS = {
+  searchEnabled: false,
+  editableValueTooltip: "",
+  editableNameTooltip: "",
+  preventDisableOnChange: true,
+  preventDescriptorModifiers: false,
+  eval: () => {}
+};
+
+/**
+ * Functions handling the audio node inspector UI.
+ */
+
+var PropertiesView = {
+
+  /**
+   * Initialization function called when the tool starts up.
+   */
+  initialize: function () {
+    this._onEval = this._onEval.bind(this);
+    this._onNodeSet = this._onNodeSet.bind(this);
+
+    window.on(EVENTS.UI_INSPECTOR_NODE_SET, this._onNodeSet);
+    this._propsView = new VariablesView($("#properties-content"), GENERIC_VARIABLES_VIEW_SETTINGS);
+    this._propsView.eval = this._onEval;
+  },
+
+  /**
+   * Destruction function called when the tool cleans up.
+   */
+  destroy: function () {
+    window.off(EVENTS.UI_INSPECTOR_NODE_SET, this._onNodeSet);
+    this._propsView = null;
+  },
+
+  /**
+   * Empties out the props view.
+   */
+  resetUI: function () {
+    this._propsView.empty();
+    this._currentNode = null;
+  },
+
+  /**
+   * Internally sets the current audio node and rebuilds appropriate
+   * views.
+   */
+  _setAudioNode: function (node) {
+    this._currentNode = node;
+    if (this._currentNode) {
+      this._buildPropertiesView();
+    }
+  },
+
+  /**
+   * Reconstructs the `Properties` tab in the inspector
+   * with the `this._currentNode` as it's source.
+   */
+  _buildPropertiesView: Task.async(function* () {
+    let propsView = this._propsView;
+    let node = this._currentNode;
+    propsView.empty();
+
+    let audioParamsScope = propsView.addScope("AudioParams");
+    let props = yield node.getParams();
+
+    // Disable AudioParams VariableView expansion
+    // when there are no props i.e. AudioDestinationNode
+    this._togglePropertiesView(!!props.length);
+
+    props.forEach(({ param, value, flags }) => {
+      let descriptor = {
+        value: value,
+        writable: !flags || !flags.readonly,
+      };
+      let item = audioParamsScope.addItem(param, descriptor);
+
+      // No items should currently display a dropdown
+      item.twisty = false;
+    });
+
+    audioParamsScope.expanded = true;
+
+    window.emit(EVENTS.UI_PROPERTIES_TAB_RENDERED, node.id);
+  }),
+
+  /**
+   * Toggles the display of the "empty" properties view when
+   * node has no properties to display.
+   */
+  _togglePropertiesView: function (show) {
+    let propsView = $("#properties-content");
+    let emptyView = $("#properties-empty");
+    (show ? propsView : emptyView).removeAttribute("hidden");
+    (show ? emptyView : propsView).setAttribute("hidden", "true");
+  },
+
+  /**
+   * Returns the scope for AudioParams in the
+   * VariablesView.
+   *
+   * @return Scope
+   */
+  _getAudioPropertiesScope: function () {
+    return this._propsView.getScopeAtIndex(0);
+  },
+
+  /**
+   * Event handlers
+   */
+
+  /**
+   * Called when the inspector view determines a node is selected.
+   */
+  _onNodeSet: function (_, id) {
+    this._setAudioNode(gAudioNodes.get(id));
+  },
+
+  /**
+   * Executed when an audio prop is changed in the UI.
+   */
+  _onEval: Task.async(function* (variable, value) {
+    let ownerScope = variable.ownerView;
+    let node = this._currentNode;
+    let propName = variable.name;
+    let error;
+
+    if (!variable._initialDescriptor.writable) {
+      error = new Error("Variable " + propName + " is not writable.");
+    } else {
+      // Cast value to proper type
+      try {
+        let number = parseFloat(value);
+        if (!isNaN(number)) {
+          value = number;
+        } else {
+          value = JSON.parse(value);
+        }
+        error = yield node.actor.setParam(propName, value);
+      }
+      catch (e) {
+        error = e;
+      }
+    }
+
+    // TODO figure out how to handle and display set prop errors
+    // and enable `test/brorwser_wa_properties-view-edit.js`
+    // Bug 994258
+    if (!error) {
+      ownerScope.get(propName).setGrip(value);
+      window.emit(EVENTS.UI_SET_PARAM, node.id, propName, value);
+    } else {
+      window.emit(EVENTS.UI_SET_PARAM_ERROR, node.id, propName, value);
+    }
+  })
+};
diff --git a/devtools/client/webaudioeditor/views/utils.js b/devtools/client/webaudioeditor/views/utils.js
new file mode 100644
index 000000000..6d6a96946
--- /dev/null
+++ b/devtools/client/webaudioeditor/views/utils.js
@@ -0,0 +1,103 @@
+/* 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";
+
+/**
+ * Takes an element in an SVG graph and iterates over
+ * ancestors until it finds the graph node container. If not found,
+ * returns null.
+ */
+
+function findGraphNodeParent(el) {
+  // Some targets may not contain `classList` property
+  if (!el.classList)
+    return null;
+
+  while (!el.classList.contains("nodes")) {
+    if (el.classList.contains("audionode"))
+      return el;
+    else
+      el = el.parentNode;
+  }
+  return null;
+}
+
+/**
+ * Object for use with `mix` into a view.
+ * Must have the following properties defined on the view:
+ * - `el`
+ * - `button`
+ * - `_collapseString`
+ * - `_expandString`
+ * - `_toggleEvent`
+ *
+ * Optional properties on the view can be defined to specify default
+ * visibility options.
+ * - `_animated`
+ * - `_delayed`
+ */
+var ToggleMixin = {
+
+  bindToggle: function () {
+    this._onToggle = this._onToggle.bind(this);
+    this.button.addEventListener("mousedown", this._onToggle, false);
+  },
+
+  unbindToggle: function () {
+    this.button.removeEventListener("mousedown", this._onToggle);
+  },
+
+  show: function () {
+    this._viewController({ visible: true });
+  },
+
+  hide: function () {
+    this._viewController({ visible: false });
+  },
+
+  hideImmediately: function () {
+    this._viewController({ visible: false, delayed: false, animated: false });
+  },
+
+  /**
+   * Returns a boolean indicating whether or not the view.
+   * is currently being shown.
+   */
+  isVisible: function () {
+    return !this.el.classList.contains("pane-collapsed");
+  },
+
+  /**
+   * Toggles the visibility of the view.
+   *
+   * @param object visible
+   *        - visible: boolean indicating whether the panel should be shown or not
+   *        - animated: boolean indiciating whether the pane should be animated
+   *        - delayed: boolean indicating whether the pane's opening should wait
+   *                   a few cycles or not
+   */
+  _viewController: function ({ visible, animated, delayed }) {
+    let flags = {
+      visible: visible,
+      animated: animated != null ? animated : !!this._animated,
+      delayed: delayed != null ? delayed : !!this._delayed,
+      callback: () => window.emit(this._toggleEvent, visible)
+    };
+
+    ViewHelpers.togglePane(flags, this.el);
+
+    if (flags.visible) {
+      this.button.classList.remove("pane-collapsed");
+      this.button.setAttribute("tooltiptext", this._collapseString);
+    }
+    else {
+      this.button.classList.add("pane-collapsed");
+      this.button.setAttribute("tooltiptext", this._expandString);
+    }
+  },
+
+  _onToggle: function () {
+    this._viewController({ visible: !this.isVisible() });
+  }
+};