Make sure newly created frames become throttled

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

Index: third_party/WebKit/Source/web/tests/FrameThrottlingTest.cpp
diff --git a/third_party/WebKit/Source/web/tests/FrameThrottlingTest.cpp b/third_party/WebKit/Source/web/tests/FrameThrottlingTest.cpp
index ae063ee128ba1fe7491c4ff8669534796e37d68c..97de77747375f97916f864ee4a5668b3f1b7be63 100644
--- a/third_party/WebKit/Source/web/tests/FrameThrottlingTest.cpp
+++ b/third_party/WebKit/Source/web/tests/FrameThrottlingTest.cpp
@@ -809,4 +809,58 @@ TEST_F(FrameThrottlingTest, SkipPaintingLayersInThrottledFrames)
     EXPECT_FALSE(displayItems2.contains(SimCanvas::Rect, "red"));
 }
 
+TEST_F(FrameThrottlingTest, ThrottleNewlyCreatedFrame)
+{
+    webView().settings()->setAcceleratedCompositingEnabled(true);
+    webView().settings()->setPreferCompositingToLCDTextEnabled(true);
+    webView().settings()->setJavaScriptEnabled(true);
+
+    SimRequest mainResource("https://example.com/", "text/html");
+    SimRequest frameResource("https://example.com/iframe.html", "text/html");
+
+    // Create an intermediate frame which is throttled.
+    loadURL("https://example.com/");
+    mainResource.complete("<iframe id=frame sandbox=allow-scripts src=iframe.html></iframe>");
+    frameResource.complete("");
+    auto* frameElement = toHTMLIFrameElement(document().getElementById("frame"));
+    frameElement->setAttribute(styleAttr, "transform: translateY(480px)");
+    compositeFrame();
+    EXPECT_TRUE(frameElement->contentDocument()->view()->canThrottleRendering());
+    auto* frameDocument = frameElement->contentDocument();
+
+    // Create a new child frame inside the throttled frame. Make sure it also
+    // has a composited layer.
+    LocalFrame* localFrame = toLocalFrame(frameElement->contentFrame());
+    localFrame->script().executeScriptInMainWorld(
+        "var frame = document.createElement('iframe');\n"
+        "frame.setAttribute('id', 'childFrame');\n"
+        "frame.setAttribute('style', 'transform: translateZ(0)');\n"
+        "document.body.appendChild(frame);\n");
+    auto* childFrameElement = toHTMLIFrameElement(frameDocument->getElementById("childFrame"));
+    auto* childFrameDocument = childFrameElement->contentDocument();
+
+    // The frame starts out as unthrottled before it is assigned to a parent.
+    EXPECT_FALSE(childFrameDocument->view()->canThrottleRendering());
+
+    // Do a full lifecycle update including paint and without allowing
+    // throttling. This will cause the creation of graphics layers for the
+    // newly created frame.
+    childFrameDocument->view()->updateAllLifecyclePhases();
+
+    // The new frame should have immediately become throttled even though we
+    // didn't run any of the intersection observers yet.
+    EXPECT_TRUE(childFrameDocument->view()->canThrottleRendering());
+
+    // Invalidate paint for all layers in all views and mutate the child frame
+    // to cause it to repaint.
+    childFrameDocument->view()->layoutView()->invalidatePaintForViewAndCompositedLayers();
+    frameDocument->view()->layoutView()->invalidatePaintForViewAndCompositedLayers();
+    document().view()->layoutView()->invalidatePaintForViewAndCompositedLayers();
+    childFrameDocument->documentElement()->setAttribute(styleAttr, "background: red");
+
+    // Compositing should not fail with a document lifecycle assertion while
+    // while trying to paint the child frame.
+    compositeFrame();
+}
+
 } // namespace blink