Bug 1615505. Forward MozAfterPaint events from child processes to the reftest harness. r=kmag,mattwoodrow

Differential Revision: https://phabricator.services.mozilla.com/D62859

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

layout/tools/reftest/ReftestFissionChild.jsm

@@ -2,8 +2,67 @@ var EXPORTED_SYMBOLS = ["ReftestFissionChild"];
 
 class ReftestFissionChild extends JSWindowActorChild {
 
+  forwardAfterPaintEventToParent(rects, originalTargetUri, dispatchToSelfAsWell) {
+    if (dispatchToSelfAsWell) {
+      let event = new this.contentWindow.CustomEvent("Reftest:MozAfterPaintFromChild",
+        {bubbles: true, detail: {rects, originalTargetUri}});
+      this.contentWindow.dispatchEvent(event);
+    }
+
+    let parentContext = this.browsingContext.parent;
+    if (parentContext) {
+      this.sendAsyncMessage("ForwardAfterPaintEvent",
+        {toBrowsingContext: parentContext, fromBrowsingContext: this.browsingContext,
+         rects, originalTargetUri});
+    }
+  }
+
+  handleEvent(evt) {
+    switch (evt.type) {
+      case "MozAfterPaint":
+        // We want to forward any after paint events to our parent document so that
+        // that it reaches the root content document where the main reftest harness
+        // code (reftest-content.js) will process it and update the canvas.
+        var rects = [];
+        for (let r of evt.clientRects) {
+            rects.push({ left: r.left, top: r.top, right: r.right, bottom: r.bottom });
+        }
+        this.forwardAfterPaintEventToParent(rects, this.document.documentURI, /* dispatchToSelfAsWell */ false);
+        break;
+    }
+  }
+
+  transformRect(transform, rect) {
+    let p1 = transform.transformPoint({x: rect.left, y: rect.top});
+    let p2 = transform.transformPoint({x: rect.right, y: rect.top});
+    let p3 = transform.transformPoint({x: rect.left, y: rect.bottom});
+    let p4 = transform.transformPoint({x: rect.right, y: rect.bottom});
+    let quad = new DOMQuad(p1, p2, p3, p4);
+    return quad.getBounds();
+  }
+
   receiveMessage(msg) {
     switch (msg.name) {
+      case "ForwardAfterPaintEventToSelfAndParent":
+      {
+        // Transform the rects from fromBrowsingContext to us.
+        // We first translate from the content rect to the border rect of the iframe.
+        let style = this.contentWindow.getComputedStyle(msg.data.fromBrowsingContext.embedderElement);
+        let translate = new DOMMatrixReadOnly().translate(
+          parseFloat(style.paddingLeft) + parseFloat(style.borderLeftWidth),
+          parseFloat(style.paddingTop) + parseFloat(style.borderTopWidth));
+
+        // Then we transform from the iframe to our root frame.
+        // We are guaranteed to be the process with the embedderElement for fromBrowsingContext.
+        let transform = msg.data.fromBrowsingContext.embedderElement.getTransformToViewport();
+        let combined = translate.multiply(transform);
+
+        let newrects = msg.data.rects.map(r => this.transformRect(combined, r))
+
+        this.forwardAfterPaintEventToParent(newrects, msg.data.originalTargetUri, /* dispatchToSelfAsWell */ true);
+        break;
+      }
+
       case "EmptyMessage":
         return undefined;
       case "UpdateLayerTree":

layout/tools/reftest/ReftestFissionParent.jsm

@@ -112,6 +112,17 @@ class ReftestFissionParent extends JSWindowActorParent {
 
   receiveMessage(msg) {
     switch (msg.name) {
+      case "ForwardAfterPaintEvent":
+      {
+        let cwg = msg.data.toBrowsingContext.currentWindowGlobal;
+        if (cwg) {
+          let a = cwg.getActor("ReftestFission");
+          if (a) {
+            a.sendAsyncMessage("ForwardAfterPaintEventToSelfAndParent", msg.data);
+          }
+        }
+        break;
+      }
       case "FlushRendering":
       {
         let promise = this.tellChildrenToFlushRendering(msg.data.browsingContext, msg.data.ignoreThrottledAnimations);

layout/tools/reftest/reftest-content.js

@@ -652,6 +652,20 @@ function WaitForTestEnd(contentRootElement, inPrintMode, spellCheckedElements, f
         }
     }
 
+    // true if rectA contains rectB
+    function Contains(rectA, rectB) {
+        return (rectA.left <= rectB.left && rectB.right <= rectA.right && rectA.top <= rectB.top && rectB.bottom <= rectA.bottom);
+    }
+    // true if some rect in rectList contains rect
+    function ContainedIn(rectList, rect) {
+        for (let i = 0; i < rectList.length; ++i) {
+            if (Contains(rectList[i], rect)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     function AfterPaintListener(event) {
         LogInfo("AfterPaintListener in " + event.target.document.location.href);
         if (event.target.document != currentDoc) {
@@ -660,23 +674,8 @@ function WaitForTestEnd(contentRootElement, inPrintMode, spellCheckedElements, f
             return;
         }
 
-        // true if rectA contains rectB
-        function Contains(rectA, rectB) {
-            return (rectA.left <= rectB.left && rectB.right <= rectA.right && rectA.top <= rectB.top && rectB.bottom <= rectA.bottom);
-        }
-        // true if some rect in rectList contains rect
-        function ContainedIn(rectList, rect) {
-            for (let i = 0; i < rectList.length; ++i) {
-                if (Contains(rectList[i], rect)) {
-                    return true;
-                }
-            }
-            return false;
-        }
-
         updateCanvasPending = true;
-        for (let i = 0; i < event.clientRects.length; ++i) {
-            let r = event.clientRects[i];
+        for (let r of event.clientRects) {
             if (ContainedIn(updateCanvasRects, r)) {
                 continue;
             }
@@ -700,6 +699,29 @@ function WaitForTestEnd(contentRootElement, inPrintMode, spellCheckedElements, f
         // call, so we don't need to do anything.
     }
 
+    function FromChildAfterPaintListener(event) {
+        LogInfo("FromChildAfterPaintListener from " + event.detail.originalTargetUri);
+
+        updateCanvasPending = true;
+        for (let r of event.detail.rects) {
+            if (ContainedIn(updateCanvasRects, r)) {
+                continue;
+            }
+
+            // Copy the rect; it's content and we are chrome, which means if the
+            // document goes away (and it can in some crashtests) our reference
+            // to it will be turned into a dead wrapper that we can't acccess.
+            updateCanvasRects.push({ left: r.left, top: r.top, right: r.right, bottom: r.bottom });
+        }
+
+        if (!operationInProgress) {
+            HandlePendingTasksAfterMakeProgress();
+        }
+        // Otherwise we know that eventually after the operation finishes we
+        // will get a MakeProgress and/or HandlePendingTasksAfterMakeProgress
+        // call, so we don't need to do anything.
+    }
+
     function AttrModifiedListener() {
         LogInfo("AttrModifiedListener fired");
         // Wait for the next return-to-event-loop before continuing --- for
@@ -719,6 +741,7 @@ function WaitForTestEnd(contentRootElement, inPrintMode, spellCheckedElements, f
     function RemoveListeners() {
         // OK, we can end the test now.
         removeEventListener("MozAfterPaint", AfterPaintListener, false);
+        removeEventListener("Reftest:MozAfterPaintFromChild", FromChildAfterPaintListener, false);
         CheckForLivenessOfContentRootElement();
         if (contentRootElement) {
             contentRootElement.removeEventListener("DOMAttrModified", AttrModifiedListener);
@@ -968,6 +991,8 @@ function WaitForTestEnd(contentRootElement, inPrintMode, spellCheckedElements, f
 
     LogInfo("WaitForTestEnd: Adding listeners");
     addEventListener("MozAfterPaint", AfterPaintListener, false);
+    addEventListener("Reftest:MozAfterPaintFromChild", FromChildAfterPaintListener, false);
+
     // If contentRootElement is null then shouldWaitForReftestWaitRemoval will
     // always return false so we don't need a listener anyway
     CheckForLivenessOfContentRootElement();

layout/tools/reftest/reftest.jsm

@@ -1576,6 +1576,9 @@ function RegisterMessageListenersAndLoadContentScript(aReload)
         },
         child: {
           moduleURI: "resource://reftest/ReftestFissionChild.jsm",
+          events: {
+            MozAfterPaint: {},
+          },
         },
         allFrames: true,
         includeChrome: true,