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Diffstat (limited to 'dom/ipc/tests/browser_ProcessPriorityManager.js')
| -rw-r--r-- | dom/ipc/tests/browser_ProcessPriorityManager.js | 892 |
1 files changed, 892 insertions, 0 deletions
diff --git a/dom/ipc/tests/browser_ProcessPriorityManager.js b/dom/ipc/tests/browser_ProcessPriorityManager.js new file mode 100644 index 0000000000..6883638dda --- /dev/null +++ b/dom/ipc/tests/browser_ProcessPriorityManager.js @@ -0,0 +1,892 @@ +/* Any copyright is dedicated to the Public Domain. + http://creativecommons.org/publicdomain/zero/1.0/ */ + +"use strict"; + +const PRIORITY_SET_TOPIC = + "process-priority-manager:TEST-ONLY:process-priority-set"; + +// Copied from Hal.cpp +const PROCESS_PRIORITY_FOREGROUND = "FOREGROUND"; +const PROCESS_PRIORITY_BACKGROUND_PERCEIVABLE = "BACKGROUND_PERCEIVABLE"; +const PROCESS_PRIORITY_BACKGROUND = "BACKGROUND"; + +// This is how many milliseconds we'll wait for a process priority +// change before we assume that it's just not happening. +const WAIT_FOR_CHANGE_TIME_MS = 2000; + +// A convenience function for getting the child ID from a browsing context. +function browsingContextChildID(bc) { + return bc.currentWindowGlobal?.domProcess.childID; +} + +/** + * This class is responsible for watching process priority changes, and + * mapping them to tabs in a single window. + */ +class TabPriorityWatcher { + /** + * Constructing a TabPriorityWatcher should happen before any tests + * start when there's only a single tab in the window. + * + * Callers must call `destroy()` on any instance that is constructed + * when the test is completed. + * + * @param tabbrowser (<tabbrowser>) + * The tabbrowser (gBrowser) for the window to be tested. + */ + constructor(tabbrowser) { + this.tabbrowser = tabbrowser; + Assert.equal( + tabbrowser.tabs.length, + 1, + "TabPriorityWatcher must be constructed in a window " + + "with a single tab to start." + ); + + // This maps from childIDs to process priorities. + this.priorityMap = new Map(); + + // The keys in this map are childIDs we're not expecting to change. + // Each value is either null (if no change has been seen) or the + // priority that the process changed to. + this.noChangeChildIDs = new Map(); + + Services.obs.addObserver(this, PRIORITY_SET_TOPIC); + } + + /** + * Cleans up lingering references for an instance of + * TabPriorityWatcher to avoid leaks. This should be called when + * finishing the test. + */ + destroy() { + Services.obs.removeObserver(this, PRIORITY_SET_TOPIC); + } + + /** + * This returns a Promise that resolves when the process with + * the given childID reaches the given priority. + * This will eventually time out if that priority is never reached. + * + * @param childID + * The childID of the process to wait on. + * @param expectedPriority (String) + * One of the PROCESS_PRIORITY_ constants defined at the + * top of this file. + * @return Promise + * @resolves undefined + * Once the browser reaches the expected priority. + */ + async waitForPriorityChange(childID, expectedPriority) { + await TestUtils.waitForCondition(() => { + let currentPriority = this.priorityMap.get(childID); + if (currentPriority == expectedPriority) { + Assert.ok( + true, + `Process with child ID ${childID} reached expected ` + + `priority: ${currentPriority}` + ); + return true; + } + return false; + }, `Waiting for process with child ID ${childID} to reach priority ${expectedPriority}`); + } + + /** + * Returns a Promise that resolves after a duration of + * WAIT_FOR_CHANGE_TIME_MS. During that time, if the process + * with the passed in child ID changes priority, a test + * failure will be registered. + * + * @param childID + * The childID of the process that we expect to not change priority. + * @return Promise + * @resolves undefined + * Once the WAIT_FOR_CHANGE_TIME_MS duration has passed. + */ + async ensureNoPriorityChange(childID) { + this.noChangeChildIDs.set(childID, null); + // eslint-disable-next-line mozilla/no-arbitrary-setTimeout + await new Promise(resolve => setTimeout(resolve, WAIT_FOR_CHANGE_TIME_MS)); + let priority = this.noChangeChildIDs.get(childID); + Assert.equal( + priority, + null, + `Should have seen no process priority change for child ID ${childID}` + ); + this.noChangeChildIDs.delete(childID); + } + + /** + * This returns a Promise that resolves when all of the processes + * of the browsing contexts in the browsing context tree + * of a particular <browser> have reached a particular priority. + * This will eventually time out if that priority is never reached. + * + * @param browser (<browser>) + * The <browser> to get the BC tree from. + * @param expectedPriority (String) + * One of the PROCESS_PRIORITY_ constants defined at the + * top of this file. + * @return Promise + * @resolves undefined + * Once the browser reaches the expected priority. + */ + async waitForBrowserTreePriority(browser, expectedPriority) { + let childIDs = new Set( + browser.browsingContext + .getAllBrowsingContextsInSubtree() + .map(browsingContextChildID) + ); + let promises = []; + for (let childID of childIDs) { + let currentPriority = this.priorityMap.get(childID); + + promises.push( + currentPriority == expectedPriority + ? this.ensureNoPriorityChange(childID) + : this.waitForPriorityChange(childID, expectedPriority) + ); + } + + await Promise.all(promises); + } + + /** + * Synchronously returns the priority of a particular child ID. + * + * @param childID + * The childID to get the content process priority for. + * @return String + * The priority of the child ID's process. + */ + currentPriority(childID) { + return this.priorityMap.get(childID); + } + + /** + * A utility function that takes a string passed via the + * PRIORITY_SET_TOPIC observer notification and extracts the + * childID and priority string. + * + * @param ppmDataString (String) + * The string data passed through the PRIORITY_SET_TOPIC observer + * notification. + * @return Object + * An object with the following properties: + * + * childID (Number) + * The ID of the content process that changed priority. + * + * priority (String) + * The priority that the content process was set to. + */ + parsePPMData(ppmDataString) { + let [childIDStr, priority] = ppmDataString.split(":"); + return { + childID: parseInt(childIDStr, 10), + priority, + }; + } + + /** nsIObserver **/ + observe(subject, topic, data) { + if (topic != PRIORITY_SET_TOPIC) { + Assert.ok(false, "TabPriorityWatcher is observing the wrong topic"); + return; + } + + let { childID, priority } = this.parsePPMData(data); + if (this.noChangeChildIDs.has(childID)) { + this.noChangeChildIDs.set(childID, priority); + } + this.priorityMap.set(childID, priority); + } +} + +let gTabPriorityWatcher; + +add_setup(async function() { + // We need to turn on testMode for the process priority manager in + // order to receive the observer notifications that this test relies on. + await SpecialPowers.pushPrefEnv({ + set: [ + ["dom.ipc.processPriorityManager.testMode", true], + ["dom.ipc.processPriorityManager.enabled", true], + ], + }); + gTabPriorityWatcher = new TabPriorityWatcher(gBrowser); +}); + +registerCleanupFunction(() => { + gTabPriorityWatcher.destroy(); + gTabPriorityWatcher = null; +}); + +/** + * Utility function that switches the current tabbrowser from one + * tab to another, and ensures that the tab that goes into the background + * has (or reaches) a particular content process priority. + * + * It is expected that the fromTab and toTab belong to two separate content + * processes. + * + * @param Object + * An object with the following properties: + * + * fromTab (<tab>) + * The tab that will be switched from to the toTab. The fromTab + * is the one that will be going into the background. + * + * toTab (<tab>) + * The tab that will be switched to from the fromTab. The toTab + * is presumed to start in the background, and will enter the + * foreground. + * + * fromTabExpectedPriority (String) + * The priority that the content process for the fromTab is + * expected to be (or reach) after the tab goes into the background. + * This should be one of the PROCESS_PRIORITY_ strings defined at the + * top of the file. + * + * @return Promise + * @resolves undefined + * Once the tab switch is complete, and the two content processes for the + * tabs have reached the expected priority levels. + */ +async function assertPriorityChangeOnBackground({ + fromTab, + toTab, + fromTabExpectedPriority, +}) { + let fromBrowser = fromTab.linkedBrowser; + let toBrowser = toTab.linkedBrowser; + + // If the tabs aren't running in separate processes, none of the + // rest of this is going to work. + Assert.notEqual( + toBrowser.frameLoader.remoteTab.osPid, + fromBrowser.frameLoader.remoteTab.osPid, + "Tabs should be running in separate processes." + ); + + let fromPromise = gTabPriorityWatcher.waitForBrowserTreePriority( + fromBrowser, + fromTabExpectedPriority + ); + let toPromise = gTabPriorityWatcher.waitForBrowserTreePriority( + toBrowser, + PROCESS_PRIORITY_FOREGROUND + ); + + await BrowserTestUtils.switchTab(gBrowser, toTab); + await Promise.all([fromPromise, toPromise]); +} + +/** + * Test that if a normal tab goes into the background, + * it has its process priority lowered to PROCESS_PRIORITY_BACKGROUND. + * Additionally, test priorityHint flag sets the process priority + * appropriately to PROCESS_PRIORITY_BACKGROUND and PROCESS_PRIORITY_FOREGROUND. + */ +add_task(async function test_normal_background_tab() { + let originalTab = gBrowser.selectedTab; + + await BrowserTestUtils.withNewTab( + "https://example.com/browser/dom/ipc/tests/file_cross_frame.html", + async browser => { + let tab = gBrowser.getTabForBrowser(browser); + await assertPriorityChangeOnBackground({ + fromTab: tab, + toTab: originalTab, + fromTabExpectedPriority: PROCESS_PRIORITY_BACKGROUND, + }); + + await assertPriorityChangeOnBackground({ + fromTab: originalTab, + toTab: tab, + fromTabExpectedPriority: PROCESS_PRIORITY_BACKGROUND, + }); + + let origtabID = browsingContextChildID( + originalTab.linkedBrowser.browsingContext + ); + + Assert.equal( + originalTab.linkedBrowser.frameLoader.remoteTab.priorityHint, + false, + "PriorityHint of the original tab should be false by default" + ); + + // Changing renderLayers doesn't change priority of the background tab. + originalTab.linkedBrowser.preserveLayers(true); + originalTab.linkedBrowser.renderLayers = true; + await new Promise(resolve => + // eslint-disable-next-line mozilla/no-arbitrary-setTimeout + setTimeout(resolve, WAIT_FOR_CHANGE_TIME_MS) + ); + Assert.equal( + gTabPriorityWatcher.currentPriority(origtabID), + PROCESS_PRIORITY_BACKGROUND, + "Tab didn't get prioritized only due to renderLayers" + ); + + // Test when priorityHint is true, the original tab priority + // becomes PROCESS_PRIORITY_FOREGROUND. + originalTab.linkedBrowser.frameLoader.remoteTab.priorityHint = true; + Assert.equal( + gTabPriorityWatcher.currentPriority(origtabID), + PROCESS_PRIORITY_FOREGROUND, + "Setting priorityHint to true should set the original tab to foreground priority" + ); + + // Test when priorityHint is false, the original tab priority + // becomes PROCESS_PRIORITY_BACKGROUND. + originalTab.linkedBrowser.frameLoader.remoteTab.priorityHint = false; + await new Promise(resolve => + // eslint-disable-next-line mozilla/no-arbitrary-setTimeout + setTimeout(resolve, WAIT_FOR_CHANGE_TIME_MS) + ); + Assert.equal( + gTabPriorityWatcher.currentPriority(origtabID), + PROCESS_PRIORITY_BACKGROUND, + "Setting priorityHint to false should set the original tab to background priority" + ); + + let tabID = browsingContextChildID(tab.linkedBrowser.browsingContext); + + // Test when priorityHint is true, the process priority of the + // active tab remains PROCESS_PRIORITY_FOREGROUND. + tab.linkedBrowser.frameLoader.remoteTab.priorityHint = true; + Assert.equal( + gTabPriorityWatcher.currentPriority(tabID), + PROCESS_PRIORITY_FOREGROUND, + "Setting priorityHint to true should maintain the new tab priority as foreground" + ); + + // Test when priorityHint is false, the process priority of the + // active tab remains PROCESS_PRIORITY_FOREGROUND. + tab.linkedBrowser.frameLoader.remoteTab.priorityHint = false; + Assert.equal( + gTabPriorityWatcher.currentPriority(tabID), + PROCESS_PRIORITY_FOREGROUND, + "Setting priorityHint to false should maintain the new tab priority as foreground" + ); + + originalTab.linkedBrowser.preserveLayers(false); + originalTab.linkedBrowser.renderLayers = false; + } + ); +}); + +// Load a simple page on the given host into a new tab. +async function loadKeepAliveTab(host) { + let tab = await BrowserTestUtils.openNewForegroundTab( + gBrowser, + host + "/browser/dom/ipc/tests/file_dummy.html" + ); + let childID = browsingContextChildID( + gBrowser.selectedBrowser.browsingContext + ); + + Assert.equal( + gTabPriorityWatcher.currentPriority(childID), + PROCESS_PRIORITY_FOREGROUND, + "Loading a new tab should make it prioritized" + ); + + if (SpecialPowers.useRemoteSubframes) { + // There must be only one process with a remote type for the tab we loaded + // to ensure that when we load a new page into the iframe with that host + // that it will end up in the same process as the initial tab. + let remoteType = gBrowser.selectedBrowser.remoteType; + await TestUtils.waitForCondition(() => { + return ( + ChromeUtils.getAllDOMProcesses().filter( + process => process.remoteType == remoteType + ).length == 1 + ); + }, `Waiting for there to be only one process with remote type ${remoteType}`); + } + + return { tab, childID }; +} + +/** + * If an iframe in a foreground tab is navigated to a new page for + * a different site, then the process of the new iframe page should + * have priority PROCESS_PRIORITY_FOREGROUND. Additionally, if Fission + * is enabled, then the old iframe page's process's priority should be + * lowered to PROCESS_PRIORITY_BACKGROUND. + */ +add_task(async function test_iframe_navigate() { + // This test (eventually) loads a page from the host topHost that has an + // iframe from iframe1Host. It then navigates the iframe to iframe2Host. + let topHost = "https://example.com"; + let iframe1Host = "https://example.org"; + let iframe2Host = "https://example.net"; + + // Before we load the final test page into a tab, we need to load pages + // from both iframe hosts into tabs. This is needed so that we are testing + // the "load a new page" part of prioritization and not the "initial + // process load" part. Additionally, it ensures that the process for the + // initial iframe page doesn't shut down once we navigate away from it, + // which will also affect its prioritization. + let { tab: iframe1Tab, childID: iframe1TabChildID } = await loadKeepAliveTab( + iframe1Host + ); + let { tab: iframe2Tab, childID: iframe2TabChildID } = await loadKeepAliveTab( + iframe2Host + ); + + await BrowserTestUtils.withNewTab( + topHost + "/browser/dom/ipc/tests/file_cross_frame.html", + async browser => { + Assert.equal( + gTabPriorityWatcher.currentPriority(iframe2TabChildID), + PROCESS_PRIORITY_BACKGROUND, + "Switching to another new tab should deprioritize the old one" + ); + + let topChildID = browsingContextChildID(browser.browsingContext); + let iframe = browser.browsingContext.children[0]; + let iframe1ChildID = browsingContextChildID(iframe); + + Assert.equal( + gTabPriorityWatcher.currentPriority(topChildID), + PROCESS_PRIORITY_FOREGROUND, + "The top level page in the new tab should be prioritized" + ); + + Assert.equal( + gTabPriorityWatcher.currentPriority(iframe1ChildID), + PROCESS_PRIORITY_FOREGROUND, + "The iframe in the new tab should be prioritized" + ); + + if (SpecialPowers.useRemoteSubframes) { + // Basic process uniqueness checks for the state after all three tabs + // are initially loaded. + Assert.notEqual( + topChildID, + iframe1ChildID, + "file_cross_frame.html should be loaded into a different process " + + "than its initial iframe" + ); + + Assert.notEqual( + topChildID, + iframe2TabChildID, + "file_cross_frame.html should be loaded into a different process " + + "than the tab containing iframe2Host" + ); + + Assert.notEqual( + iframe1ChildID, + iframe2TabChildID, + "The initial iframe loaded by file_cross_frame.html should be " + + "loaded into a different process than the tab containing " + + "iframe2Host" + ); + + // Note: this assertion depends on our process selection logic. + // Specifically, that we reuse an existing process for an iframe if + // possible. + Assert.equal( + iframe1TabChildID, + iframe1ChildID, + "Both pages loaded in iframe1Host should be in the same process" + ); + } + + // Do a cross-origin navigation in the iframe in the foreground tab. + let iframe2URI = iframe2Host + "/browser/dom/ipc/tests/file_dummy.html"; + let loaded = BrowserTestUtils.browserLoaded(browser, true, iframe2URI); + await SpecialPowers.spawn(iframe, [iframe2URI], async function( + _iframe2URI + ) { + content.location = _iframe2URI; + }); + await loaded; + + let iframe2ChildID = browsingContextChildID(iframe); + let iframe1Priority = gTabPriorityWatcher.currentPriority(iframe1ChildID); + let iframe2Priority = gTabPriorityWatcher.currentPriority(iframe2ChildID); + + if (SpecialPowers.useRemoteSubframes) { + // Basic process uniqueness check for the state after navigating the + // iframe. There's no need to check the top level pages because they + // have not navigated. + // + // iframe1ChildID != iframe2ChildID is implied by: + // iframe1ChildID != iframe2TabChildID + // iframe2TabChildID == iframe2ChildID + // + // iframe2ChildID != topChildID is implied by: + // topChildID != iframe2TabChildID + // iframe2TabChildID == iframe2ChildID + + // Note: this assertion depends on our process selection logic. + // Specifically, that we reuse an existing process for an iframe if + // possible. If that changes, this test may need to be carefully + // rewritten, as the whole point of the test is to check what happens + // with the priority manager when an iframe shares a process with + // a page in another tab. + Assert.equal( + iframe2TabChildID, + iframe2ChildID, + "Both pages loaded in iframe2Host should be in the same process" + ); + + // Now that we've established the relationship between the various + // processes, we can finally check that the priority manager is doing + // the right thing. + Assert.equal( + iframe1Priority, + PROCESS_PRIORITY_BACKGROUND, + "The old iframe process should have been deprioritized" + ); + } else { + Assert.equal( + iframe1ChildID, + iframe2ChildID, + "Navigation should not have switched processes" + ); + } + + Assert.equal( + iframe2Priority, + PROCESS_PRIORITY_FOREGROUND, + "The new iframe process should be prioritized" + ); + } + ); + + await BrowserTestUtils.removeTab(iframe2Tab); + await BrowserTestUtils.removeTab(iframe1Tab); +}); + +/** + * Test that a cross-group navigation properly preserves the process priority. + * The goal of this test is to check that the code related to mPriorityActive in + * CanonicalBrowsingContext::ReplacedBy works correctly, but in practice the + * prioritization code in SetRenderLayers will also make this test pass, though + * that prioritization happens slightly later. + */ +add_task(async function test_cross_group_navigate() { + // This page is same-site with the page we're going to cross-group navigate to. + let coopPage = + "https://example.com/browser/dom/tests/browser/file_coop_coep.html"; + + // Load it as a top level tab so that we don't accidentally get the initial + // load prioritization. + let backgroundTab = await BrowserTestUtils.openNewForegroundTab( + gBrowser, + coopPage + ); + let backgroundTabChildID = browsingContextChildID( + gBrowser.selectedBrowser.browsingContext + ); + + Assert.equal( + gTabPriorityWatcher.currentPriority(backgroundTabChildID), + PROCESS_PRIORITY_FOREGROUND, + "Loading a new tab should make it prioritized" + ); + + await BrowserTestUtils.withNewTab( + "https://example.org/browser/dom/ipc/tests/file_cross_frame.html", + async browser => { + Assert.equal( + gTabPriorityWatcher.currentPriority(backgroundTabChildID), + PROCESS_PRIORITY_BACKGROUND, + "Switching to a new tab should deprioritize the old one" + ); + + let dotOrgChildID = browsingContextChildID(browser.browsingContext); + + // Do a cross-group navigation. + BrowserTestUtils.loadURI(browser, coopPage); + await BrowserTestUtils.browserLoaded(browser); + + let coopChildID = browsingContextChildID(browser.browsingContext); + let coopPriority = gTabPriorityWatcher.currentPriority(coopChildID); + let dotOrgPriority = gTabPriorityWatcher.currentPriority(dotOrgChildID); + + Assert.equal( + backgroundTabChildID, + coopChildID, + "The same site should get loaded into the same process" + ); + Assert.notEqual( + dotOrgChildID, + coopChildID, + "Navigation should have switched processes" + ); + Assert.equal( + dotOrgPriority, + PROCESS_PRIORITY_BACKGROUND, + "The old page process should have been deprioritized" + ); + Assert.equal( + coopPriority, + PROCESS_PRIORITY_FOREGROUND, + "The new page process should be prioritized" + ); + } + ); + + await BrowserTestUtils.removeTab(backgroundTab); +}); + +/** + * Test that if a tab with video goes into the background, + * it has its process priority lowered to + * PROCESS_PRIORITY_BACKGROUND_PERCEIVABLE if it has no audio, + * and that it has its priority remain at + * PROCESS_PRIORITY_FOREGROUND if it does have audio. + */ +add_task(async function test_video_background_tab() { + let originalTab = gBrowser.selectedTab; + + await BrowserTestUtils.withNewTab("https://example.com", async browser => { + // Let's load up a video in the tab, but mute it, so that this tab should + // reach PROCESS_PRIORITY_BACKGROUND_PERCEIVABLE. + await SpecialPowers.spawn(browser, [], async () => { + let video = content.document.createElement("video"); + video.src = "https://example.net/browser/dom/ipc/tests/short.mp4"; + video.muted = true; + content.document.body.appendChild(video); + // We'll loop the video to avoid it ending before the test is done. + video.loop = true; + await video.play(); + }); + + let tab = gBrowser.getTabForBrowser(browser); + + // The tab with the muted video should reach + // PROCESS_PRIORITY_BACKGROUND_PERCEIVABLE when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: tab, + toTab: originalTab, + fromTabExpectedPriority: PROCESS_PRIORITY_BACKGROUND_PERCEIVABLE, + }); + + // Now switch back. The initial blank tab should reach + // PROCESS_PRIORITY_BACKGROUND when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: originalTab, + toTab: tab, + fromTabExpectedPriority: PROCESS_PRIORITY_BACKGROUND, + }); + + // Let's unmute the video now. + await SpecialPowers.spawn(browser, [], async () => { + let video = content.document.querySelector("video"); + video.muted = false; + }); + + // The tab with the unmuted video should stay at + // PROCESS_PRIORITY_FOREGROUND when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: tab, + toTab: originalTab, + fromTabExpectedPriority: PROCESS_PRIORITY_FOREGROUND, + }); + + // Now switch back. The initial blank tab should reach + // PROCESS_PRIORITY_BACKGROUND when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: originalTab, + toTab: tab, + fromTabExpectedPriority: PROCESS_PRIORITY_BACKGROUND, + }); + }); +}); + +/** + * Test that if a tab with a playing <audio> element goes into + * the background, the process priority does not change, unless + * that audio is muted (in which case, it reaches + * PROCESS_PRIORITY_BACKGROUND). + */ +add_task(async function test_audio_background_tab() { + let originalTab = gBrowser.selectedTab; + + await BrowserTestUtils.withNewTab("https://example.com", async browser => { + // Let's load up some audio in the tab, but mute it, so that this tab should + // reach PROCESS_PRIORITY_BACKGROUND. + await SpecialPowers.spawn(browser, [], async () => { + let audio = content.document.createElement("audio"); + audio.src = "https://example.net/browser/dom/ipc/tests/owl.mp3"; + audio.muted = true; + content.document.body.appendChild(audio); + // We'll loop the audio to avoid it ending before the test is done. + audio.loop = true; + await audio.play(); + }); + + let tab = gBrowser.getTabForBrowser(browser); + + // The tab with the muted audio should reach + // PROCESS_PRIORITY_BACKGROUND when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: tab, + toTab: originalTab, + fromTabExpectedPriority: PROCESS_PRIORITY_BACKGROUND, + }); + + // Now switch back. The initial blank tab should reach + // PROCESS_PRIORITY_BACKGROUND when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: originalTab, + toTab: tab, + fromTabExpectedPriority: PROCESS_PRIORITY_BACKGROUND, + }); + + // Now unmute the audio. Unfortuntely, there's a bit of a race here, + // since the wakelock on the audio element is released and then + // re-acquired if the audio reaches its end and loops around. This + // will cause an unexpected priority change on the content process. + // + // To avoid this race, we'll seek the audio back to the beginning, + // and lower its playback rate to the minimum to increase the + // likelihood that the check completes before the audio loops around. + await SpecialPowers.spawn(browser, [], async () => { + let audio = content.document.querySelector("audio"); + let seeked = ContentTaskUtils.waitForEvent(audio, "seeked"); + audio.muted = false; + // 0.25 is the minimum playback rate that still keeps the audio audible. + audio.playbackRate = 0.25; + audio.currentTime = 0; + await seeked; + }); + + // The tab with the unmuted audio should stay at + // PROCESS_PRIORITY_FOREGROUND when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: tab, + toTab: originalTab, + fromTabExpectedPriority: PROCESS_PRIORITY_FOREGROUND, + }); + + // Now switch back. The initial blank tab should reach + // PROCESS_PRIORITY_BACKGROUND when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: originalTab, + toTab: tab, + fromTabExpectedPriority: PROCESS_PRIORITY_BACKGROUND, + }); + }); +}); + +/** + * Test that if a tab with a WebAudio playing goes into the background, + * the process priority does not change, unless that WebAudio context is + * suspended. + */ +add_task(async function test_web_audio_background_tab() { + let originalTab = gBrowser.selectedTab; + + await BrowserTestUtils.withNewTab("https://example.com", async browser => { + // Let's synthesize a basic square wave as WebAudio. + await SpecialPowers.spawn(browser, [], async () => { + let audioCtx = new content.AudioContext(); + let oscillator = audioCtx.createOscillator(); + oscillator.type = "square"; + oscillator.frequency.setValueAtTime(440, audioCtx.currentTime); + oscillator.connect(audioCtx.destination); + oscillator.start(); + while (audioCtx.state != "running") { + info(`wait until AudioContext starts running`); + await new Promise(r => (audioCtx.onstatechange = r)); + } + // we'll stash the AudioContext away so that it's easier to access + // in the next SpecialPowers.spawn. + content.audioCtx = audioCtx; + }); + + let tab = gBrowser.getTabForBrowser(browser); + + // The tab with the WebAudio should stay at + // PROCESS_PRIORITY_FOREGROUND when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: tab, + toTab: originalTab, + fromTabExpectedPriority: PROCESS_PRIORITY_FOREGROUND, + }); + + // Now switch back. The initial blank tab should reach + // PROCESS_PRIORITY_BACKGROUND when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: originalTab, + toTab: tab, + fromTabExpectedPriority: PROCESS_PRIORITY_BACKGROUND, + }); + + // Now suspend the WebAudio. This will cause it to stop + // playing. + await SpecialPowers.spawn(browser, [], async () => { + content.audioCtx.suspend(); + }); + + // The tab with the suspended WebAudio should reach + // PROCESS_PRIORITY_BACKGROUND when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: tab, + toTab: originalTab, + fromTabExpectedPriority: PROCESS_PRIORITY_BACKGROUND, + }); + + // Now switch back. The initial blank tab should reach + // PROCESS_PRIORITY_BACKGROUND when backgrounded. + await assertPriorityChangeOnBackground({ + fromTab: originalTab, + toTab: tab, + fromTabExpectedPriority: PROCESS_PRIORITY_BACKGROUND, + }); + }); +}); + +/** + * Test that foreground tab's process priority isn't changed when going back to + * a bfcached session history entry. + */ +add_task(async function test_audio_background_tab() { + let page1 = "https://example.com"; + let page2 = page1 + "/?2"; + + await BrowserTestUtils.withNewTab(page1, async browser => { + let childID = browsingContextChildID(browser.browsingContext); + Assert.equal( + gTabPriorityWatcher.currentPriority(childID), + PROCESS_PRIORITY_FOREGROUND, + "Loading a new tab should make it prioritized." + ); + let loaded = BrowserTestUtils.browserLoaded(browser, false, page2); + BrowserTestUtils.loadURI(browser, page2); + await loaded; + + childID = browsingContextChildID(browser.browsingContext); + Assert.equal( + gTabPriorityWatcher.currentPriority(childID), + PROCESS_PRIORITY_FOREGROUND, + "Loading a new page should keep the tab prioritized." + ); + + let pageShowPromise = BrowserTestUtils.waitForContentEvent( + browser, + "pageshow" + ); + browser.goBack(); + await pageShowPromise; + + childID = browsingContextChildID(browser.browsingContext); + Assert.equal( + gTabPriorityWatcher.currentPriority(childID), + PROCESS_PRIORITY_FOREGROUND, + "Loading a page from the bfcache should keep the tab prioritized." + ); + }); +}); |