Update widget geometries when transforming a layer

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 "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/frame/FrameView.h"
 #include "core/html/HTMLIFrameElement.h"
 #include "platform/testing/URLTestHelpers.h"
 #include "platform/testing/UnitTestHelpers.h"
@@ skipping 421 matching lines @@
     EXPECT_FALSE(document().view()->shouldScrollOnMainThread());
 
     // Scroll down to unthrottle the frame.
     webView().mainFrameImpl()->frameView()->setScrollPosition(DoublePoint(0, 480), ProgrammaticScroll);
     document().view()->updateAllLifecyclePhases();
     testing::runPendingTasks();
     // The fixed background in the throttled sub frame should be considered.
     EXPECT_TRUE(document().view()->shouldScrollOnMainThread());
 }
 
+TEST_F(FrameThrottlingTest, UnthrottleByTransformingWithoutLayout)
+{
+    webView().settings()->setAcceleratedCompositingEnabled(true);
+
+    // Create a hidden frame which is throttled.
+    SimRequest mainResource("https://example.com/", "text/html");
+    SimRequest frameResource("https://example.com/iframe.html", "text/html");
+
+    loadURL("https://example.com/");
+    mainResource.complete("<iframe id=frame sandbox src=iframe.html></iframe>");
+    frameResource.complete("");
+
+    // Move the frame offscreen to throttle it.
+    auto* frameElement = toHTMLIFrameElement(document().getElementById("frame"));
+    frameElement->setAttribute(styleAttr, "transform: translateY(480px)");
+    EXPECT_FALSE(frameElement->contentDocument()->view()->canThrottleRendering());
+    compositeFrame();
+    EXPECT_TRUE(frameElement->contentDocument()->view()->canThrottleRendering());
+
+    // Make the frame visible by changing its transform. This doesn't cause a
+    // layout, but should still unthrottle the frame.
+    frameElement->setAttribute(styleAttr, "transform: translateY(0px)");
+    compositeFrame();
+    EXPECT_FALSE(frameElement->contentDocument()->view()->canThrottleRendering());
+}
+
 } // namespace blink