Fix partial painting with render pipeline throttling

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 193 matching lines @@
 
     // Move the frame offscreen to throttle it.
     frameElement->setAttribute(styleAttr, "transform: translateY(480px)");
     compositeFrame();
     EXPECT_TRUE(frameElement->contentDocument()->view()->canThrottleRendering());
 
     // Mutating the throttled frame should not cause an animation to be scheduled.
     frameElement->contentDocument()->documentElement()->setAttribute(styleAttr, "background: green");
     EXPECT_FALSE(compositor().needsAnimate());
 
-    // Moving the frame back on screen to unthrottle it.
+    // Move the frame back on screen to unthrottle it.
     frameElement->setAttribute(styleAttr, "");
     EXPECT_TRUE(compositor().needsAnimate());
 
     // The first frame we composite after unthrottling won't contain the
     // frame's new contents because unthrottling happens at the end of the
     // lifecycle update. We need to do another composite to refresh the frame's
     // contents.
     auto displayItems2 = compositeFrame();
     EXPECT_FALSE(displayItems2.contains(SimCanvas::Rect, "green"));
     EXPECT_TRUE(compositor().needsAnimate());
@@ skipping 19 matching lines @@
 
     // Change the size of a div in the throttled frame.
     auto* divElement = frameElement->contentDocument()->getElementById("div");
     divElement->setAttribute(styleAttr, "width: 50px");
 
     // Querying the width of the div should do a synchronous layout update even
     // though the frame is being throttled.
     EXPECT_EQ(50, divElement->clientWidth());
 }
 
+TEST_F(FrameThrottlingTest, UnthrottlingTriggersRepaint)
+{
+    // 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("<style> html { background: green; } </style>");
+
+    // Move the frame offscreen to throttle it.
+    auto* frameElement = toHTMLIFrameElement(document().getElementById("frame"));
+    frameElement->setAttribute(styleAttr, "transform: translateY(480px)");
+    EXPECT_FALSE(frameElement->contentDocument()->view()->shouldThrottleRendering());
+    compositeFrame();
+    EXPECT_TRUE(frameElement->contentDocument()->view()->shouldThrottleRendering());
+
+    // Scroll down to unthrottle the frame. The first frame we composite after
+    // scrolling won't contain the frame yet, but will schedule another repaint.
+    webView().mainFrameImpl()->frameView()->setScrollPosition(DoublePoint(0, 480), ProgrammaticScroll);
+    auto displayItems = compositeFrame();
+    EXPECT_FALSE(displayItems.contains(SimCanvas::Rect, "green"));
+
+    // Now the frame contents should be visible again.
+    auto displayItems2 = compositeFrame();
+    EXPECT_TRUE(displayItems2.contains(SimCanvas::Rect, "green"));
+}
+
+TEST_F(FrameThrottlingTest, ChangeStyleInThrottledFrame)
+{
+    // 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("<style> html { background: red; } </style>");
+
+    // Move the frame offscreen to throttle it.
+    auto* frameElement = toHTMLIFrameElement(document().getElementById("frame"));
+    frameElement->setAttribute(styleAttr, "transform: translateY(480px)");
+    EXPECT_FALSE(frameElement->contentDocument()->view()->shouldThrottleRendering());
+    compositeFrame();
+    EXPECT_TRUE(frameElement->contentDocument()->view()->shouldThrottleRendering());
+
+    // Change the background color of the frame's contents from red to green.
+    frameElement->contentDocument()->body()->setAttribute(styleAttr, "background: green");
+
+    // Scroll down to unthrottle the frame.
+    webView().mainFrameImpl()->frameView()->setScrollPosition(DoublePoint(0, 480), ProgrammaticScroll);
+    auto displayItems = compositeFrame();
+    EXPECT_FALSE(displayItems.contains(SimCanvas::Rect, "red"));
+    EXPECT_FALSE(displayItems.contains(SimCanvas::Rect, "green"));
+
+    // Make sure the new style shows up instead of the old one.
+    auto displayItems2 = compositeFrame();
+    EXPECT_TRUE(displayItems2.contains(SimCanvas::Rect, "green"));
+}
+
 TEST(RemoteFrameThrottlingTest, ThrottledLocalRoot)
 {
     FrameTestHelpers::TestWebViewClient viewClient;
     WebViewImpl* webView = WebViewImpl::create(&viewClient);
     webView->resize(WebSize(640, 480));
 
     // Create a remote root frame with a local child frame.
     FrameTestHelpers::TestWebRemoteFrameClient remoteClient;
     webView->setMainFrame(remoteClient.frame());
     remoteClient.frame()->setReplicatedOrigin(WebSecurityOrigin::createUnique());
@@ skipping 27 matching lines @@
 
     // Update the lifecycle again. The frame's lifecycle should not advance
     // because of throttling even though it is the local root.
     frameView->updateAllLifecyclePhases();
     testing::runPendingTasks();
     EXPECT_EQ(DocumentLifecycle::VisualUpdatePending, frameDocument->lifecycle().state());
     webView->close();
 }
 
 } // namespace blink