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+/* 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/. */
+
+// This file is loaded into the browser window scope.
+/* eslint-env mozilla/browser-window */
+
+/**
+ * Controls the "full zoom" setting and its site-specific preferences.
+ */
+var FullZoom = {
+ // Identifies the setting in the content prefs database.
+ name: "browser.content.full-zoom",
+
+ // browser.zoom.siteSpecific preference cache
+ // Enabling privacy.resistFingerprinting implies disabling browser.zoom.siteSpecific.
+ _siteSpecificPref: undefined,
+
+ // browser.zoom.updateBackgroundTabs preference cache
+ updateBackgroundTabs: undefined,
+
+ // This maps the browser to monotonically increasing integer
+ // tokens. _browserTokenMap[browser] is increased each time the zoom is
+ // changed in the browser. See _getBrowserToken and _ignorePendingZoomAccesses.
+ _browserTokenMap: new WeakMap(),
+
+ // Stores initial locations if we receive onLocationChange
+ // events before we're initialized.
+ _initialLocations: new WeakMap(),
+
+ get siteSpecific() {
+ if (this._siteSpecificPref === undefined) {
+ this._siteSpecificPref =
+ !Services.prefs.getBoolPref("privacy.resistFingerprinting") &&
+ Services.prefs.getBoolPref("browser.zoom.siteSpecific");
+ }
+ return this._siteSpecificPref;
+ },
+
+ // nsISupports
+
+ QueryInterface: ChromeUtils.generateQI([
+ "nsIObserver",
+ "nsIContentPrefObserver",
+ "nsISupportsWeakReference",
+ ]),
+
+ // Initialization & Destruction
+
+ init: function FullZoom_init() {
+ gBrowser.addEventListener("DoZoomEnlargeBy10", this);
+ gBrowser.addEventListener("DoZoomReduceBy10", this);
+ window.addEventListener("MozScaleGestureComplete", this);
+
+ // Register ourselves with the service so we know when our pref changes.
+ this._cps2 = Cc["@mozilla.org/content-pref/service;1"].getService(
+ Ci.nsIContentPrefService2
+ );
+ this._cps2.addObserverForName(this.name, this);
+
+ this.updateBackgroundTabs = Services.prefs.getBoolPref(
+ "browser.zoom.updateBackgroundTabs"
+ );
+
+ // Listen for changes to the browser.zoom branch so we can enable/disable
+ // updating background tabs and per-site saving and restoring of zoom levels.
+ Services.prefs.addObserver("browser.zoom.", this, true);
+
+ // Also need to listen to privacy.resistFingerprinting in order to update
+ // this._siteSpecificPref.
+ Services.prefs.addObserver("privacy.resistFingerprinting", this, true);
+
+ // If we received onLocationChange events for any of the current browsers
+ // before we were initialized we want to replay those upon initialization.
+ for (let browser of gBrowser.browsers) {
+ if (this._initialLocations.has(browser)) {
+ this.onLocationChange(...this._initialLocations.get(browser), browser);
+ }
+ }
+
+ // This should be nulled after initialization.
+ this._initialLocations = null;
+ },
+
+ destroy: function FullZoom_destroy() {
+ Services.prefs.removeObserver("browser.zoom.", this);
+ this._cps2.removeObserverForName(this.name, this);
+ gBrowser.removeEventListener("DoZoomEnlargeBy10", this);
+ gBrowser.removeEventListener("DoZoomReduceBy10", this);
+ window.removeEventListener("MozScaleGestureComplete", this);
+ },
+
+ // Event Handlers
+
+ // EventListener
+
+ handleEvent: function FullZoom_handleEvent(event) {
+ switch (event.type) {
+ case "DoZoomEnlargeBy10":
+ this.changeZoomBy(this._getTargetedBrowser(event), 0.1);
+ break;
+ case "DoZoomReduceBy10":
+ this.changeZoomBy(this._getTargetedBrowser(event), -0.1);
+ break;
+ case "MozScaleGestureComplete": {
+ let nonDefaultScalingZoom = event.detail != 1.0;
+ this.updateCommands(nonDefaultScalingZoom);
+ break;
+ }
+ }
+ },
+
+ // nsIObserver
+
+ observe(aSubject, aTopic, aData) {
+ switch (aTopic) {
+ case "nsPref:changed":
+ switch (aData) {
+ case "privacy.resistFingerprinting":
+ // fall through
+ case "browser.zoom.siteSpecific":
+ // Invalidate pref cache.
+ this._siteSpecificPref = undefined;
+ break;
+ case "browser.zoom.updateBackgroundTabs":
+ this.updateBackgroundTabs = Services.prefs.getBoolPref(
+ "browser.zoom.updateBackgroundTabs"
+ );
+ break;
+ case "browser.zoom.full": {
+ this.updateCommands();
+ break;
+ }
+ }
+ break;
+ }
+ },
+
+ // nsIContentPrefObserver
+
+ onContentPrefSet: function FullZoom_onContentPrefSet(
+ aGroup,
+ aName,
+ aValue,
+ aIsPrivate
+ ) {
+ this._onContentPrefChanged(aGroup, aValue, aIsPrivate);
+ },
+
+ onContentPrefRemoved: function FullZoom_onContentPrefRemoved(
+ aGroup,
+ aName,
+ aIsPrivate
+ ) {
+ this._onContentPrefChanged(aGroup, undefined, aIsPrivate);
+ },
+
+ /**
+ * Appropriately updates the zoom level after a content preference has
+ * changed.
+ *
+ * @param aGroup The group of the changed preference.
+ * @param aValue The new value of the changed preference. Pass undefined to
+ * indicate the preference's removal.
+ */
+ _onContentPrefChanged: function FullZoom__onContentPrefChanged(
+ aGroup,
+ aValue,
+ aIsPrivate
+ ) {
+ if (this._isNextContentPrefChangeInternal) {
+ // Ignore changes that FullZoom itself makes. This works because the
+ // content pref service calls callbacks before notifying observers, and it
+ // does both in the same turn of the event loop.
+ delete this._isNextContentPrefChangeInternal;
+ return;
+ }
+
+ let browser = gBrowser.selectedBrowser;
+ if (!browser.currentURI) {
+ return;
+ }
+
+ if (this._isPDFViewer(browser)) {
+ return;
+ }
+
+ let ctxt = this._loadContextFromBrowser(browser);
+ let domain = this._cps2.extractDomain(browser.currentURI.spec);
+ if (aGroup) {
+ if (aGroup == domain && ctxt.usePrivateBrowsing == aIsPrivate) {
+ this._applyPrefToZoom(aValue, browser);
+ }
+ return;
+ }
+
+ // If the current page doesn't have a site-specific preference, then its
+ // zoom should be set to the new global preference now that the global
+ // preference has changed.
+ let hasPref = false;
+ let token = this._getBrowserToken(browser);
+ this._cps2.getByDomainAndName(browser.currentURI.spec, this.name, ctxt, {
+ handleResult() {
+ hasPref = true;
+ },
+ handleCompletion: () => {
+ if (!hasPref && token.isCurrent) {
+ this._applyPrefToZoom(undefined, browser);
+ }
+ },
+ });
+ },
+
+ // location change observer
+
+ /**
+ * Called when the location of a tab changes.
+ * When that happens, we need to update the current zoom level if appropriate.
+ *
+ * @param aURI
+ * A URI object representing the new location.
+ * @param aIsTabSwitch
+ * Whether this location change has happened because of a tab switch.
+ * @param aBrowser
+ * (optional) browser object displaying the document
+ */
+ onLocationChange: function FullZoom_onLocationChange(
+ aURI,
+ aIsTabSwitch,
+ aBrowser
+ ) {
+ let browser = aBrowser || gBrowser.selectedBrowser;
+
+ // If we haven't been initialized yet but receive an onLocationChange
+ // notification then let's store and replay it upon initialization.
+ if (this._initialLocations) {
+ this._initialLocations.set(browser, [aURI, aIsTabSwitch]);
+ return;
+ }
+
+ // Ignore all pending async zoom accesses in the browser. Pending accesses
+ // that started before the location change will be prevented from applying
+ // to the new location.
+ this._ignorePendingZoomAccesses(browser);
+
+ if (!aURI || (aIsTabSwitch && !this.siteSpecific)) {
+ this._notifyOnLocationChange(browser);
+ return;
+ }
+
+ if (aURI.spec == "about:blank") {
+ if (
+ !browser.contentPrincipal ||
+ browser.contentPrincipal.isNullPrincipal
+ ) {
+ // For an about:blank with a null principal, zooming any amount does not
+ // make any sense - so simply do 100%.
+ this._applyPrefToZoom(
+ 1,
+ browser,
+ this._notifyOnLocationChange.bind(this, browser)
+ );
+ } else {
+ // If it's not a null principal, there may be content loaded into it,
+ // so use the global pref. This will avoid a cps2 roundtrip if we've
+ // already loaded the global pref once. Really, this should probably
+ // use the contentPrincipal's origin if it's an http(s) principal.
+ // (See bug 1457597)
+ this._applyPrefToZoom(
+ undefined,
+ browser,
+ this._notifyOnLocationChange.bind(this, browser)
+ );
+ }
+ return;
+ }
+
+ // Media documents should always start at 1, and are not affected by prefs.
+ if (!aIsTabSwitch && browser.isSyntheticDocument) {
+ ZoomManager.setZoomForBrowser(browser, 1);
+ // _ignorePendingZoomAccesses already called above, so no need here.
+ this._notifyOnLocationChange(browser);
+ return;
+ }
+
+ // The PDF viewer zooming isn't handled by `ZoomManager`, ensure that the
+ // browser zoom level always gets reset to 100% on load (to prevent the
+ // UI elements of the PDF viewer from being zoomed in/out on load).
+ if (this._isPDFViewer(browser)) {
+ this._applyPrefToZoom(
+ 1,
+ browser,
+ this._notifyOnLocationChange.bind(this, browser)
+ );
+ return;
+ }
+
+ // See if the zoom pref is cached.
+ let ctxt = this._loadContextFromBrowser(browser);
+ let pref = this._cps2.getCachedByDomainAndName(aURI.spec, this.name, ctxt);
+ if (pref) {
+ this._applyPrefToZoom(
+ pref.value,
+ browser,
+ this._notifyOnLocationChange.bind(this, browser)
+ );
+ return;
+ }
+
+ // It's not cached, so we have to asynchronously fetch it.
+ let value = undefined;
+ let token = this._getBrowserToken(browser);
+ this._cps2.getByDomainAndName(aURI.spec, this.name, ctxt, {
+ handleResult(resultPref) {
+ value = resultPref.value;
+ },
+ handleCompletion: () => {
+ if (!token.isCurrent) {
+ this._notifyOnLocationChange(browser);
+ return;
+ }
+ this._applyPrefToZoom(
+ value,
+ browser,
+ this._notifyOnLocationChange.bind(this, browser)
+ );
+ },
+ });
+ },
+
+ // update state of zoom menu items
+
+ /**
+ * Updates the current windows Zoom commands for zooming in, zooming out
+ * and resetting the zoom level.
+ *
+ * @param {boolean} [forceResetEnabled=false]
+ * Set to true if the zoom reset command should be enabled regardless of
+ * whether or not the ZoomManager.zoom level is at 1.0. This is specifically
+ * for when using scaling zoom via the pinch gesture which doesn't cause
+ * the ZoomManager.zoom level to change.
+ * @returns Promise
+ * @resolves undefined
+ */
+ updateCommands: async function FullZoom_updateCommands(
+ forceResetEnabled = false
+ ) {
+ let zoomLevel = ZoomManager.zoom;
+ let defaultZoomLevel = await ZoomUI.getGlobalValue();
+ let reduceCmd = document.getElementById("cmd_fullZoomReduce");
+ if (zoomLevel == ZoomManager.MIN) {
+ reduceCmd.setAttribute("disabled", "true");
+ } else {
+ reduceCmd.removeAttribute("disabled");
+ }
+
+ let enlargeCmd = document.getElementById("cmd_fullZoomEnlarge");
+ if (zoomLevel == ZoomManager.MAX) {
+ enlargeCmd.setAttribute("disabled", "true");
+ } else {
+ enlargeCmd.removeAttribute("disabled");
+ }
+
+ let resetCmd = document.getElementById("cmd_fullZoomReset");
+ if (zoomLevel == defaultZoomLevel && !forceResetEnabled) {
+ resetCmd.setAttribute("disabled", "true");
+ } else {
+ resetCmd.removeAttribute("disabled");
+ }
+
+ let fullZoomCmd = document.getElementById("cmd_fullZoomToggle");
+ if (!ZoomManager.useFullZoom) {
+ fullZoomCmd.setAttribute("checked", "true");
+ } else {
+ fullZoomCmd.setAttribute("checked", "false");
+ }
+ },
+
+ // Setting & Pref Manipulation
+
+ sendMessageToPDFViewer(browser, name) {
+ try {
+ browser.sendMessageToActor(name, {}, "Pdfjs");
+ } catch (ex) {
+ console.error(ex);
+ }
+ },
+
+ /**
+ * If browser in reader mode sends message to reader in order to decrease font size,
+ * Otherwise reduces the zoom level of the page in the current browser.
+ */
+ async reduce() {
+ let browser = gBrowser.selectedBrowser;
+ if (browser.currentURI.spec.startsWith("about:reader")) {
+ browser.sendMessageToActor("Reader:ZoomOut", {}, "AboutReader");
+ } else if (this._isPDFViewer(browser)) {
+ this.sendMessageToPDFViewer(browser, "PDFJS:ZoomOut");
+ } else {
+ ZoomManager.reduce();
+ this._ignorePendingZoomAccesses(browser);
+ await this._applyZoomToPref(browser);
+ }
+ },
+
+ /**
+ * If browser in reader mode sends message to reader in order to increase font size,
+ * Otherwise enlarges the zoom level of the page in the current browser.
+ */
+ async enlarge() {
+ let browser = gBrowser.selectedBrowser;
+ if (browser.currentURI.spec.startsWith("about:reader")) {
+ browser.sendMessageToActor("Reader:ZoomIn", {}, "AboutReader");
+ } else if (this._isPDFViewer(browser)) {
+ this.sendMessageToPDFViewer(browser, "PDFJS:ZoomIn");
+ } else {
+ ZoomManager.enlarge();
+ this._ignorePendingZoomAccesses(browser);
+ await this._applyZoomToPref(browser);
+ }
+ },
+
+ /**
+ * If browser in reader mode sends message to reader in order to increase font size,
+ * Otherwise enlarges the zoom level of the page in the current browser.
+ * This function is not async like reduce/enlarge, because it is invoked by our
+ * event handler. This means that the call to _applyZoomToPref is not awaited and
+ * will happen asynchronously.
+ */
+ changeZoomBy(aBrowser, aValue) {
+ if (aBrowser.currentURI.spec.startsWith("about:reader")) {
+ const message = aValue > 0 ? "Reader::ZoomIn" : "Reader:ZoomOut";
+ aBrowser.sendMessageToActor(message, {}, "AboutReader");
+ return;
+ } else if (this._isPDFViewer(aBrowser)) {
+ const message = aValue > 0 ? "PDFJS::ZoomIn" : "PDFJS:ZoomOut";
+ this.sendMessageToPDFViewer(aBrowser, message);
+ return;
+ }
+ let zoom = ZoomManager.getZoomForBrowser(aBrowser);
+ zoom += aValue;
+ if (zoom < ZoomManager.MIN) {
+ zoom = ZoomManager.MIN;
+ } else if (zoom > ZoomManager.MAX) {
+ zoom = ZoomManager.MAX;
+ }
+ ZoomManager.setZoomForBrowser(aBrowser, zoom);
+ this._ignorePendingZoomAccesses(aBrowser);
+ this._applyZoomToPref(aBrowser);
+ },
+
+ /**
+ * Sets the zoom level for the given browser to the given floating
+ * point value, where 1 is the default zoom level.
+ */
+ setZoom(value, browser = gBrowser.selectedBrowser) {
+ if (this._isPDFViewer(browser)) {
+ return;
+ }
+ ZoomManager.setZoomForBrowser(browser, value);
+ this._ignorePendingZoomAccesses(browser);
+ this._applyZoomToPref(browser);
+ },
+
+ /**
+ * Sets the zoom level of the page in the given browser to the global zoom
+ * level.
+ *
+ * @return A promise which resolves when the zoom reset has been applied.
+ */
+ reset: function FullZoom_reset(browser = gBrowser.selectedBrowser) {
+ let forceValue;
+ if (browser.currentURI.spec.startsWith("about:reader")) {
+ browser.sendMessageToActor("Reader:ResetZoom", {}, "AboutReader");
+ } else if (this._isPDFViewer(browser)) {
+ this.sendMessageToPDFViewer(browser, "PDFJS:ZoomReset");
+ // Ensure that the UI elements of the PDF viewer won't be zoomed in/out
+ // on reset, even if/when browser default zoom value is not set to 100%.
+ forceValue = 1;
+ }
+ let token = this._getBrowserToken(browser);
+ let result = ZoomUI.getGlobalValue().then(value => {
+ if (token.isCurrent) {
+ ZoomManager.setZoomForBrowser(browser, forceValue || value);
+ this._ignorePendingZoomAccesses(browser);
+ }
+ });
+ this._removePref(browser);
+ return result;
+ },
+
+ resetScalingZoom: function FullZoom_resetScaling(
+ browser = gBrowser.selectedBrowser
+ ) {
+ browser.browsingContext?.resetScalingZoom();
+ },
+
+ /**
+ * Set the zoom level for a given browser.
+ *
+ * Per nsPresContext::setFullZoom, we can set the zoom to its current value
+ * without significant impact on performance, as the setting is only applied
+ * if it differs from the current setting. In fact getting the zoom and then
+ * checking ourselves if it differs costs more.
+ *
+ * And perhaps we should always set the zoom even if it was more expensive,
+ * since nsDocumentViewer::SetTextZoom claims that child documents can have
+ * a different text zoom (although it would be unusual), and it implies that
+ * those child text zooms should get updated when the parent zoom gets set,
+ * and perhaps the same is true for full zoom
+ * (although nsDocumentViewer::SetFullZoom doesn't mention it).
+ *
+ * So when we apply new zoom values to the browser, we simply set the zoom.
+ * We don't check first to see if the new value is the same as the current
+ * one.
+ *
+ * @param aValue The zoom level value.
+ * @param aBrowser The zoom is set in this browser. Required.
+ * @param aCallback If given, it's asynchronously called when complete.
+ */
+ _applyPrefToZoom: function FullZoom__applyPrefToZoom(
+ aValue,
+ aBrowser,
+ aCallback
+ ) {
+ // The browser is sometimes half-destroyed because this method is called
+ // by content pref service callbacks, which themselves can be called at any
+ // time, even after browsers are closed.
+ if (
+ !aBrowser.mInitialized ||
+ aBrowser.isSyntheticDocument ||
+ (!this.siteSpecific && aBrowser.tabHasCustomZoom)
+ ) {
+ this._executeSoon(aCallback);
+ return;
+ }
+
+ if (aValue !== undefined && this.siteSpecific) {
+ ZoomManager.setZoomForBrowser(aBrowser, this._ensureValid(aValue));
+ this._ignorePendingZoomAccesses(aBrowser);
+ this._executeSoon(aCallback);
+ return;
+ }
+
+ // Above, we check if site-specific zoom is enabled before setting
+ // the tab browser zoom, however global zoom should work independent
+ // of the site-specific pref, so we do no checks here.
+ let token = this._getBrowserToken(aBrowser);
+ ZoomUI.getGlobalValue().then(value => {
+ if (token.isCurrent) {
+ ZoomManager.setZoomForBrowser(aBrowser, value);
+ this._ignorePendingZoomAccesses(aBrowser);
+ }
+ this._executeSoon(aCallback);
+ });
+ },
+
+ /**
+ * Saves the zoom level of the page in the given browser to the content
+ * prefs store.
+ *
+ * @param browser The zoom of this browser will be saved. Required.
+ */
+ _applyZoomToPref: function FullZoom__applyZoomToPref(browser) {
+ if (!this.siteSpecific || browser.isSyntheticDocument) {
+ // If site-specific zoom is disabled, we have called this function
+ // to adjust our tab's zoom level. It is now considered "custom"
+ // and we mark that here.
+ browser.tabHasCustomZoom = !this.siteSpecific;
+ return null;
+ }
+
+ return new Promise(resolve => {
+ this._cps2.set(
+ browser.currentURI.spec,
+ this.name,
+ ZoomManager.getZoomForBrowser(browser),
+ this._loadContextFromBrowser(browser),
+ {
+ handleCompletion: () => {
+ this._isNextContentPrefChangeInternal = true;
+ resolve();
+ },
+ }
+ );
+ });
+ },
+
+ /**
+ * Removes from the content prefs store the zoom level of the given browser.
+ *
+ * @param browser The zoom of this browser will be removed. Required.
+ */
+ _removePref: function FullZoom__removePref(browser) {
+ if (browser.isSyntheticDocument) {
+ return;
+ }
+ let ctxt = this._loadContextFromBrowser(browser);
+ this._cps2.removeByDomainAndName(browser.currentURI.spec, this.name, ctxt, {
+ handleCompletion: () => {
+ this._isNextContentPrefChangeInternal = true;
+ },
+ });
+ },
+
+ // Utilities
+
+ /**
+ * Returns the zoom change token of the given browser. Asynchronous
+ * operations that access the given browser's zoom should use this method to
+ * capture the token before starting and use token.isCurrent to determine if
+ * it's safe to access the zoom when done. If token.isCurrent is false, then
+ * after the async operation started, either the browser's zoom was changed or
+ * the browser was destroyed, and depending on what the operation is doing, it
+ * may no longer be safe to set and get its zoom.
+ *
+ * @param browser The token of this browser will be returned.
+ * @return An object with an "isCurrent" getter.
+ */
+ _getBrowserToken: function FullZoom__getBrowserToken(browser) {
+ let map = this._browserTokenMap;
+ if (!map.has(browser)) {
+ map.set(browser, 0);
+ }
+ return {
+ token: map.get(browser),
+ get isCurrent() {
+ // At this point, the browser may have been destructed and unbound but
+ // its outer ID not removed from the map because outer-window-destroyed
+ // hasn't been received yet. In that case, the browser is unusable, it
+ // has no properties, so return false. Check for this case by getting a
+ // property, say, docShell.
+ return map.get(browser) === this.token && browser.mInitialized;
+ },
+ };
+ },
+
+ /**
+ * Returns the browser that the supplied zoom event is associated with.
+ * @param event The zoom event.
+ * @return The associated browser element, if one exists, otherwise null.
+ */
+ _getTargetedBrowser: function FullZoom__getTargetedBrowser(event) {
+ let target = event.originalTarget;
+
+ // With remote content browsers, the event's target is the browser
+ // we're looking for.
+ const XUL_NS =
+ "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+ if (
+ window.XULElement.isInstance(target) &&
+ target.localName == "browser" &&
+ target.namespaceURI == XUL_NS
+ ) {
+ return target;
+ }
+
+ // With in-process content browsers, the event's target is the content
+ // document.
+ if (target.nodeType == Node.DOCUMENT_NODE) {
+ return target.ownerGlobal.docShell.chromeEventHandler;
+ }
+
+ throw new Error("Unexpected zoom event source");
+ },
+
+ /**
+ * Increments the zoom change token for the given browser so that pending
+ * async operations know that it may be unsafe to access they zoom when they
+ * finish.
+ *
+ * @param browser Pending accesses in this browser will be ignored.
+ */
+ _ignorePendingZoomAccesses: function FullZoom__ignorePendingZoomAccesses(
+ browser
+ ) {
+ let map = this._browserTokenMap;
+ map.set(browser, (map.get(browser) || 0) + 1);
+ },
+
+ _ensureValid: function FullZoom__ensureValid(aValue) {
+ // Note that undefined is a valid value for aValue that indicates a known-
+ // not-to-exist value.
+ if (isNaN(aValue)) {
+ return 1;
+ }
+
+ if (aValue < ZoomManager.MIN) {
+ return ZoomManager.MIN;
+ }
+
+ if (aValue > ZoomManager.MAX) {
+ return ZoomManager.MAX;
+ }
+
+ return aValue;
+ },
+
+ /**
+ * Gets the load context from the given Browser.
+ *
+ * @param Browser The Browser whose load context will be returned.
+ * @return The nsILoadContext of the given Browser.
+ */
+ _loadContextFromBrowser: function FullZoom__loadContextFromBrowser(browser) {
+ return browser.loadContext;
+ },
+
+ /**
+ * Asynchronously broadcasts "browser-fullZoom:location-change" so that
+ * listeners can be notified when the zoom levels on those pages change.
+ * The notification is always asynchronous so that observers are guaranteed a
+ * consistent behavior.
+ */
+ _notifyOnLocationChange: function FullZoom__notifyOnLocationChange(browser) {
+ this._executeSoon(function() {
+ Services.obs.notifyObservers(browser, "browser-fullZoom:location-change");
+ });
+ },
+
+ _executeSoon: function FullZoom__executeSoon(callback) {
+ if (!callback) {
+ return;
+ }
+ Services.tm.dispatchToMainThread(callback);
+ },
+
+ _isPDFViewer(browser) {
+ return !!(
+ browser.contentPrincipal.spec == "resource://pdf.js/web/viewer.html"
+ );
+ },
+};