Disallow throttling while running requestAnimationFrame callbacks

third_party/WebKit/Source/web/tests/FrameThrottlingTest.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "bindings/core/v8/ScriptController.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/html/HTMLIFrameElement.h"
@@ skipping 791 matching lines @@
 
     // Simulate the paint for a graphics layer being externally invalidated
     // (e.g., by video playback).
     frameDocument->view()->layoutView()->invalidatePaintForViewAndCompositedLayers();
 
     // The layer inside the throttled frame should not get painted.
     auto displayItems2 = compositeFrame();
     EXPECT_FALSE(displayItems2.contains(SimCanvas::Rect, "red"));
 }
 
+TEST_F(FrameThrottlingTest, SynchronousLayoutInRequestAnimationFrameCallback)
+{
+    webView().settings()->setJavaScriptEnabled(true);
+
+    // Prepare a page with two cross origin frames (from the same origin so they
+    // are able to access eachother).
+    SimRequest mainResource("https://example.com/", "text/html");
+    SimRequest firstFrameResource("https://thirdparty.com/first.html", "text/html");
+    SimRequest secondFrameResource("https://thirdparty.com/second.html", "text/html");
+    loadURL("https://example.com/");
+    mainResource.complete(
+        "<iframe id=first name=first src='https://thirdparty.com/first.html'></iframe>\n"
+        "<iframe id=second name=second src='https://thirdparty.com/second.html'></iframe>");
+
+    // The first frame contains just a simple div. This frame will be made
+    // throttled.
+    firstFrameResource.complete("<div id=d>first frame</div>");
+
+    // The second page has a script which, inside a requestAnimationFrame
+    // callback, mutates the first (throttled) frame's contents and then
+    // requests a synchronous style computation of that first frame.
+    secondFrameResource.complete(
+        "<script>"
+        "window.addEventListener('load', function() {\n"
+        // Set up the rAF callback after a delay. Otherwise it will get serviced
+        // as a part of the first composition pass.
+        "  window.setTimeout(function() {\n"

[esprehn, 2016/05/19 18:53:59]

I don't think we want this delay, just run the right sequence of calls inside
the test. Ex. Composite the first frame or something. You shouldn't need to
setTimeout, your test is the scheduler.

[Sami, 2016/05/19 19:05:20]

Good point, done.

+        "    window.requestAnimationFrame(function() {\n"
+        "      var throttledFrame = window.parent.frames['first'];\n"
+        "      throttledFrame.document.documentElement.style = 'margin: 50px';\n"
+        "      throttledFrame.document.querySelector('#d').getBoundingClientRect();\n"
+        "    });\n"
+        "  }, 0);\n"
+        "});\n"
+        "</script>\n");
+
+    // Throttle the first frame.
+    auto* firstFrameElement = toHTMLIFrameElement(document().getElementById("first"));
+    firstFrameElement->setAttribute(styleAttr, "transform: translateY(480px)");
+    compositeFrame();
+    EXPECT_TRUE(firstFrameElement->contentDocument()->view()->canThrottleRendering());
+
+    // Service the requestAnimationFrame for the second frame. This should not
+    // result in an unexpected lifecycle state even if the first frame is
+    // throttled during the requestAnimationFrame callback.
+    compositeFrame();
+}
+
 } // namespace blink