Bug 1597765 - support auto scroll in out of process frames r=Gijs

Differential Revision: https://phabricator.services.mozilla.com/D54596

--HG--
rename : toolkit/modules/AutoScrollController.jsm => toolkit/actors/AutoScrollChild.jsm
extra : moz-landing-system : lando

toolkit/actors/AutoScrollChild.jsm

@@ -5,10 +5,12 @@
 
 const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 
-var EXPORTED_SYMBOLS = ["AutoScrollController"];
+var EXPORTED_SYMBOLS = ["AutoScrollChild"];
+
+class AutoScrollChild extends JSWindowActorChild {
+  constructor() {
+    super();
 
-class AutoScrollController {
-  constructor(global) {
     this._scrollable = null;
     this._scrolldir = "";
     this._startX = null;
@@ -18,10 +20,9 @@ class AutoScrollController {
     this._lastFrame = null;
     this._autoscrollHandledByApz = false;
     this._scrollId = null;
-    this._global = global;
-    this.autoscrollLoop = this.autoscrollLoop.bind(this);
 
-    global.addMessageListener("Autoscroll:Stop", this);
+    this.observer = new AutoScrollObserver(this);
+    this.autoscrollLoop = this.autoscrollLoop.bind(this);
   }
 
   isAutoscrollBlocker(node) {
@@ -145,16 +146,22 @@ class AutoScrollController {
         this._scrolldir = direction;
         this._scrollable = aNode.ownerGlobal;
       } else if (aNode.ownerGlobal.frameElement) {
-        // FIXME(emilio): This won't work with Fission.
+        // Note, in case of out of process iframes frameElement is null, and
+        // a caller is supposed to communicate to iframe's parent on its own to
+        // support cross process scrolling.
         this.findNearestScrollableElement(aNode.ownerGlobal.frameElement);
       }
     }
   }
 
-  startScroll(event) {
+  async startScroll(event) {
     this.findNearestScrollableElement(event.originalTarget);
-
     if (!this._scrollable) {
+      this.sendAsyncMessage("Autoscroll:MaybeStartInParent", {
+        browsingContextId: this.browsingContext.id,
+        screenX: event.screenX,
+        screenY: event.screenY,
+      });
       return;
     }
 
@@ -180,20 +187,23 @@ class AutoScrollController {
       // No view ID - leave this._scrollId as null. Receiving side will check.
     }
     let presShellId = domUtils.getPresShellId();
-    let [result] = this._global.sendSyncMessage("Autoscroll:Start", {
-      scrolldir: this._scrolldir,
-      screenX: event.screenX,
-      screenY: event.screenY,
-      scrollId: this._scrollId,
-      presShellId,
-    });
-    if (!result.autoscrollEnabled) {
+    let { autoscrollEnabled, usingApz } = await this.sendQuery(
+      "Autoscroll:Start",
+      {
+        scrolldir: this._scrolldir,
+        screenX: event.screenX,
+        screenY: event.screenY,
+        scrollId: this._scrollId,
+        presShellId,
+      }
+    );
+    if (!autoscrollEnabled) {
       this._scrollable = null;
       return;
     }
 
-    Services.els.addSystemEventListener(this._global, "mousemove", this, true);
-    this._global.addEventListener("pagehide", this, true);
+    Services.els.addSystemEventListener(this.document, "mousemove", this, true);
+    this.document.addEventListener("pagehide", this, true);
 
     this._ignoreMouseEvents = true;
     this._startX = event.screenX;
@@ -202,9 +212,9 @@ class AutoScrollController {
     this._screenY = event.screenY;
     this._scrollErrorX = 0;
     this._scrollErrorY = 0;
-    this._autoscrollHandledByApz = result.usingApz;
+    this._autoscrollHandledByApz = usingApz;
 
-    if (!result.usingApz) {
+    if (!usingApz) {
       // If the browser didn't hand the autoscroll off to APZ,
       // scroll here in the main thread.
       this.startMainThreadScroll();
@@ -212,12 +222,16 @@ class AutoScrollController {
       // Even if the browser did hand the autoscroll to APZ,
       // APZ might reject it in which case it will notify us
       // and we need to take over.
-      Services.obs.addObserver(this, "autoscroll-rejected-by-apz");
+      Services.obs.addObserver(this.observer, "autoscroll-rejected-by-apz");
+    }
+
+    if (Cu.isInAutomation) {
+      Services.obs.notifyObservers(content, "autoscroll-start");
     }
   }
 
   startMainThreadScroll() {
-    let content = this._global.content;
+    let content = this.document.defaultView;
     this._lastFrame = content.performance.now();
     content.requestAnimationFrame(this.autoscrollLoop);
   }
@@ -228,14 +242,17 @@ class AutoScrollController {
       this._scrollable = null;
 
       Services.els.removeSystemEventListener(
-        this._global,
+        this.document,
         "mousemove",
         this,
         true
       );
-      this._global.removeEventListener("pagehide", this, true);
+      this.document.removeEventListener("pagehide", this, true);
       if (this._autoscrollHandledByApz) {
-        Services.obs.removeObserver(this, "autoscroll-rejected-by-apz");
+        Services.obs.removeObserver(
+          this.observer,
+          "autoscroll-rejected-by-apz"
+        );
       }
     }
   }
@@ -306,6 +323,8 @@ class AutoScrollController {
       this._screenY = event.screenY;
     } else if (event.type == "mousedown") {
       if (
+        event.isTrusted & !event.defaultPrevented &&
+        event.button == 1 &&
         !this._scrollable &&
         !this.isAutoscrollBlocker(event.originalTarget)
       ) {
@@ -315,14 +334,28 @@ class AutoScrollController {
       if (this._scrollable) {
         var doc = this._scrollable.ownerDocument || this._scrollable.document;
         if (doc == event.target) {
-          this._global.sendAsyncMessage("Autoscroll:Cancel");
+          this.sendAsyncMessage("Autoscroll:Cancel");
+          this.stopScroll();
         }
       }
     }
   }
 
   receiveMessage(msg) {
+    let data = msg.data;
     switch (msg.name) {
+      case "Autoscroll:MaybeStart":
+        for (let child of this.browsingContext.getChildren()) {
+          if (data.browsingContextId == child.id) {
+            this.startScroll({
+              screenX: data.screenX,
+              screenY: data.screenY,
+              originalTarget: child.embedderElement,
+            });
+            break;
+          }
+        }
+        break;
       case "Autoscroll:Stop": {
         this.stopScroll();
         break;
@@ -330,14 +363,24 @@ class AutoScrollController {
     }
   }
 
-  observe(subject, topic, data) {
-    if (topic === "autoscroll-rejected-by-apz") {
-      // The caller passes in the scroll id via 'data'.
-      if (data == this._scrollId) {
-        this._autoscrollHandledByApz = false;
-        this.startMainThreadScroll();
-        Services.obs.removeObserver(this, "autoscroll-rejected-by-apz");
-      }
+  rejectedByApz(data) {
+    // The caller passes in the scroll id via 'data'.
+    if (data == this._scrollId) {
+      this._autoscrollHandledByApz = false;
+      this.startMainThreadScroll();
+      Services.obs.removeObserver(this.observer, "autoscroll-rejected-by-apz");
+    }
+  }
+}
+
+class AutoScrollObserver {
+  constructor(actor) {
+    this.actor = actor;
+  }
+
+  observe(subject, topic, data) {
+    if (topic === "autoscroll-rejected-by-apz") {
+      this.actor.rejectedByApz(data);
     }
   }
 }

toolkit/actors/AutoScrollParent.jsm

@@ -0,0 +1,33 @@
+/* vim: set ts=2 sw=2 sts=2 et tw=80: */
+/* 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";
+
+var EXPORTED_SYMBOLS = ["AutoScrollParent"];
+
+class AutoScrollParent extends JSWindowActorParent {
+  receiveMessage(msg) {
+    let browser = this.manager.browsingContext.top.embedderElement;
+    if (!browser) {
+      return null;
+    }
+
+    let data = msg.data;
+    switch (msg.name) {
+      case "Autoscroll:Start":
+        return Promise.resolve(browser.startScroll(data));
+      case "Autoscroll:MaybeStartInParent":
+        let parent = this.browsingContext.parent;
+        if (parent) {
+          let actor = parent.currentWindowGlobal.getActor("AutoScroll");
+          actor.sendAsyncMessage("Autoscroll:MaybeStart", data);
+        }
+        break;
+      case "Autoscroll:Cancel":
+        browser.cancelScroll();
+        break;
+    }
+    return null;
+  }
+}

toolkit/actors/moz.build

@@ -7,6 +7,9 @@
 with Files('**'):
     BUG_COMPONENT = ('Toolkit', 'General')
 
+with Files('AutoScroll*.jsm'):
+    BUG_COMPONENT = ('Core', 'Panning and Zooming')
+
 with Files('Finder*.jsm'):
     BUG_COMPONENT = ('Toolkit', 'Find Toolbar')
 
@@ -25,6 +28,8 @@ FINAL_TARGET_FILES.actors += [
     'AutoCompleteParent.jsm',
     'AutoplayChild.jsm',
     'AutoplayParent.jsm',
+    'AutoScrollChild.jsm',
+    'AutoScrollParent.jsm',
     'BrowserElementChild.jsm',
     'BrowserElementParent.jsm',
     'ControllersChild.jsm',

toolkit/content/browser-content.js

@@ -6,34 +6,11 @@
 /* eslint-env mozilla/frame-script */
 /* eslint no-unused-vars: ["error", {args: "none"}] */
 
+/* exported Services */
 var { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+
 var { ActorManagerChild } = ChromeUtils.import(
   "resource://gre/modules/ActorManagerChild.jsm"
 );
 
 ActorManagerChild.attach(this);
-
-ChromeUtils.defineModuleGetter(
-  this,
-  "AutoScrollController",
-  "resource://gre/modules/AutoScrollController.jsm"
-);
-
-var global = this;
-
-var AutoScrollListener = {
-  handleEvent(event) {
-    if (event.isTrusted & !event.defaultPrevented && event.button == 1) {
-      if (!this._controller) {
-        this._controller = new AutoScrollController(global);
-      }
-      this._controller.handleEvent(event);
-    }
-  },
-};
-Services.els.addSystemEventListener(
-  global,
-  "mousedown",
-  AutoScrollListener,
-  true
-);

toolkit/content/tests/browser/browser_bug295977_autoscroll_overflow.js

@@ -160,6 +160,26 @@ body > div > div {width: 1000px;height: 1000px;}\
       expected: expectScrollNone,
       testwindow: true,
     },
+    {
+      // Test: scroll is initiated in out of process iframe having no scrollable area
+      dataUri:
+        "data:text/html," +
+        encodeURIComponent(`
+<!doctype html>
+<head><meta content="text/html;charset=utf-8"></head><body>
+<div id="scroller" style="width: 300px; height: 300px; overflow-y: scroll; overflow-x: hidden; border: solid 1px blue;">
+  <iframe id="noscroll-outofprocess-iframe" src="https://example.com/browser/toolkit/content/tests/browser/file_contentTitle.html"
+          style="border: solid 1px green; margin: 2px;"></iframe>
+  <div style="width: 100%; height: 200px;"></div>
+</div></body>
+        `),
+    },
+    {
+      elem: "noscroll-outofprocess-iframe",
+      // We expect the div to scroll vertically, not the iframe's window.
+      expected: expectScrollVert,
+      scrollable: "scroller",
+    },
   ];
 
   for (let test of allTests) {
@@ -187,19 +207,28 @@ body > div > div {width: 1000px;height: 1000px;}\
 
     // This ensures bug 605127 is fixed: pagehide in an unrelated document
     // should not cancel the autoscroll.
-    await SpecialPowers.spawn(gBrowser.selectedBrowser, [], async function() {
-      var iframe = content.document.getElementById("iframe");
+    await ContentTask.spawn(
+      gBrowser.selectedBrowser,
+      { waitForAutoScrollStart: test.expected != expectScrollNone },
+      async ({ waitForAutoScrollStart }) => {
+        var iframe = content.document.getElementById("iframe");
 
-      if (iframe) {
-        var e = new iframe.contentWindow.PageTransitionEvent("pagehide", {
-          bubbles: true,
-          cancelable: true,
-          persisted: false,
-        });
-        iframe.contentDocument.dispatchEvent(e);
-        iframe.contentDocument.documentElement.dispatchEvent(e);
+        if (iframe) {
+          var e = new iframe.contentWindow.PageTransitionEvent("pagehide", {
+            bubbles: true,
+            cancelable: true,
+            persisted: false,
+          });
+          iframe.contentDocument.dispatchEvent(e);
+          iframe.contentDocument.documentElement.dispatchEvent(e);
+        }
+        if (waitForAutoScrollStart) {
+          await new Promise(resolve =>
+            Services.obs.addObserver(resolve, "autoscroll-start")
+          );
+        }
       }
-    });
+    );
 
     is(
       document.activeElement,
@@ -265,7 +294,7 @@ body > div > div {width: 1000px;height: 1000px;}\
         {
           scrollVert,
           scrollHori,
-          elemid: test.elem,
+          elemid: test.scrollable || test.elem,
           checkWindow: test.testwindow,
         },
       ],

toolkit/content/widgets/browser-custom-element.js

@@ -1344,8 +1344,6 @@
           "PopupBlocking:UpdateBlockedPopups",
           this
         );
-        this.messageManager.addMessageListener("Autoscroll:Start", this);
-        this.messageManager.addMessageListener("Autoscroll:Cancel", this);
         this.messageManager.addMessageListener(
           "UnselectedTabHover:Toggle",
           this
@@ -1418,41 +1416,6 @@
           this.updateBlockedPopups();
           break;
         }
-        case "Autoscroll:Start": {
-          if (!this.autoscrollEnabled) {
-            return { autoscrollEnabled: false, usingApz: false };
-          }
-          this.startScroll(data.scrolldir, data.screenX, data.screenY);
-          let usingApz = false;
-          if (
-            this.isRemoteBrowser &&
-            data.scrollId != null &&
-            this.mPrefs.getBoolPref("apz.autoscroll.enabled", false)
-          ) {
-            let { remoteTab } = this.frameLoader;
-            if (remoteTab) {
-              // If APZ is handling the autoscroll, it may decide to cancel
-              // it of its own accord, so register an observer to allow it
-              // to notify us of that.
-              var os = Services.obs;
-              os.addObserver(this.observer, "apz:cancel-autoscroll", true);
-
-              usingApz = remoteTab.startApzAutoscroll(
-                data.screenX,
-                data.screenY,
-                data.scrollId,
-                data.presShellId
-              );
-            }
-            // Save the IDs for later
-            this._autoScrollScrollId = data.scrollId;
-            this._autoScrollPresShellId = data.presShellId;
-          }
-          return { autoscrollEnabled: true, usingApz };
-        }
-        case "Autoscroll:Cancel":
-          this._autoScrollPopup.hidePopup();
-          break;
         case "UnselectedTabHover:Toggle":
           this._shouldSendUnselectedTabHover = data.enable
             ? ++this._unselectedTabHoverMessageListenerCount > 0
@@ -1659,7 +1622,8 @@
         window.removeEventListener("keydown", this, true);
         window.removeEventListener("keypress", this, true);
         window.removeEventListener("keyup", this, true);
-        this.messageManager.sendAsyncMessage("Autoscroll:Stop");
+
+        this.sendMessageToActor("Autoscroll:Stop", {}, "AutoScroll", true);
 
         try {
           Services.obs.removeObserver(this.observer, "apz:cancel-autoscroll");
@@ -1690,7 +1654,11 @@
       return popup;
     }
 
-    startScroll(scrolldir, screenX, screenY) {
+    startScroll({ scrolldir, screenX, screenY, scrollId, presShellId }) {
+      if (!this.autoscrollEnabled) {
+        return { autoscrollEnabled: false, usingApz: false };
+      }
+
       const POPUP_SIZE = 32;
       if (!this._autoScrollPopup) {
         if (this.hasAttribute("autoscrollpopup")) {
@@ -1772,6 +1740,40 @@
       window.addEventListener("keydown", this, true);
       window.addEventListener("keypress", this, true);
       window.addEventListener("keyup", this, true);
+
+      let usingApz = false;
+      if (
+        this.isRemoteBrowser &&
+        scrollId != null &&
+        this.mPrefs.getBoolPref("apz.autoscroll.enabled", false)
+      ) {
+        let { remoteTab } = this.frameLoader;
+        if (remoteTab) {
+          // If APZ is handling the autoscroll, it may decide to cancel
+          // it of its own accord, so register an observer to allow it
+          // to notify us of that.
+          Services.obs.addObserver(
+            this.observer,
+            "apz:cancel-autoscroll",
+            true
+          );
+
+          usingApz = remoteTab.startApzAutoscroll(
+            screenX,
+            screenY,
+            scrollId,
+            presShellId
+          );
+        }
+        // Save the IDs for later
+        this._autoScrollScrollId = scrollId;
+        this._autoScrollPresShellId = presShellId;
+      }
+      return { autoscrollEnabled: true, usingApz };
+    }
+
+    cancelScroll() {
+      this._autoScrollPopup.hidePopup();
     }
 
     handleEvent(aEvent) {

toolkit/modules/ActorManagerParent.jsm

@@ -90,6 +90,21 @@ let ACTORS = {
     allFrames: true,
   },
 
+  AutoScroll: {
+    parent: {
+      moduleURI: "resource://gre/actors/AutoScrollParent.jsm",
+    },
+
+    child: {
+      moduleURI: "resource://gre/actors/AutoScrollChild.jsm",
+      events: {
+        mousedown: { capture: true, mozSystemGroup: true },
+      },
+    },
+
+    allFrames: true,
+  },
+
   BrowserElement: {
     parent: {
       moduleURI: "resource://gre/actors/BrowserElementParent.jsm",

toolkit/modules/moz.build

@@ -48,9 +48,6 @@ with Files('tests/xpcshell/test_UpdateUtils*.js'):
 with Files('AsyncPrefs.jsm'):
     BUG_COMPONENT = ('Core', 'Security: Process Sandboxing')
 
-with Files('AutoScrollController.jsm'):
-    BUG_COMPONENT = ('Core', 'Panning and Zooming')
-
 with Files('CharsetMenu.jsm'):
     BUG_COMPONENT = ('Firefox', 'Toolbars and Customization')
 
@@ -165,7 +162,6 @@ EXTRA_JS_MODULES += [
     'ActorManagerParent.jsm',
     'AppMenuNotifications.jsm',
     'AsyncPrefs.jsm',
-    'AutoScrollController.jsm',
     'BinarySearch.jsm',
     'BrowserUtils.jsm',
     'CanonicalJSON.jsm',