Use intersection observer to control frame 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 "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 432 matching lines @@
     FrameTestHelpers::loadFrame(localFrame, baseURL.utf8() + "simple_div.html");
 
     FrameView* frameView = toWebLocalFrameImpl(localFrame)->frameView();
     EXPECT_TRUE(frameView->frame().isLocalRoot());
 
     // Enable throttling for the child frame.
     frameView->setFrameRect(IntRect(0, 480, frameView->width(), frameView->height()));
     frameView->frame().securityContext()->setSecurityOrigin(SecurityOrigin::createUnique());
     frameView->updateAllLifecyclePhases();
     testing::runPendingTasks();
-    EXPECT_TRUE(frameView->canThrottleRendering());
+    // TODO(skyostil): Intersection observers don't work for remote frames (crbug.com/615156).
+    EXPECT_FALSE(frameView->canThrottleRendering());
 
     Document* frameDocument = frameView->frame().document();
     EXPECT_EQ(DocumentLifecycle::PaintClean, frameDocument->lifecycle().state());
 
     // Mutate the local child frame contents.
     auto* divElement = frameDocument->getElementById("div");
     divElement->setAttribute(styleAttr, "width: 50px");
     EXPECT_EQ(DocumentLifecycle::VisualUpdatePending, frameDocument->lifecycle().state());
 
     // Update the lifecycle again. The frame's lifecycle should not advance
     // because of throttling even though it is the local root.
+    // TODO(skyostil): Intersection observers don't work for remote frames (crbug.com/615156).
     DocumentLifecycle::AllowThrottlingScope throttlingScope(frameDocument->lifecycle());
     frameView->updateAllLifecyclePhases();
     testing::runPendingTasks();
-    EXPECT_EQ(DocumentLifecycle::VisualUpdatePending, frameDocument->lifecycle().state());
+    EXPECT_EQ(DocumentLifecycle::PaintClean, frameDocument->lifecycle().state());
     webView->close();
 }
 
 TEST_F(FrameThrottlingTest, ScrollingCoordinatorShouldSkipThrottledFrame)
 {
     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");
@@ skipping 282 matching lines @@
     auto* childFrameElement = toHTMLIFrameElement(frameElement->contentDocument()->getElementById("child-frame"));
     frameElement->setAttribute(styleAttr, "transform: translateY(480px)");
     compositor().beginFrame();
     EXPECT_FALSE(frameElement->contentDocument()->view()->canThrottleRendering());
     EXPECT_FALSE(childFrameElement->contentDocument()->view()->canThrottleRendering());
 
     // Only run the intersection observer for the parent frame. Both frames
     // should immediately become throttled. This simulates the case where a task
     // such as BeginMainFrame runs in the middle of dispatching intersection
     // observer notifications.
-    frameElement->contentDocument()->view()->notifyRenderThrottlingObserversForTesting();
+    frameElement->contentDocument()->view()->updateRenderThrottlingStatusForTesting();
     EXPECT_TRUE(frameElement->contentDocument()->view()->canThrottleRendering());
     EXPECT_TRUE(childFrameElement->contentDocument()->view()->canThrottleRendering());
 
     // Both frames should still be throttled after the second notification.
-    childFrameElement->contentDocument()->view()->notifyRenderThrottlingObserversForTesting();
+    childFrameElement->contentDocument()->view()->updateRenderThrottlingStatusForTesting();
     EXPECT_TRUE(frameElement->contentDocument()->view()->canThrottleRendering());
     EXPECT_TRUE(childFrameElement->contentDocument()->view()->canThrottleRendering());
+
+    // Move the frame back on screen but don't update throttling yet.
+    frameElement->setAttribute(styleAttr, "transform: translateY(0px)");
+    compositor().beginFrame();
+    EXPECT_TRUE(frameElement->contentDocument()->view()->canThrottleRendering());
+    EXPECT_TRUE(childFrameElement->contentDocument()->view()->canThrottleRendering());
+
+    // Update throttling for the child. It should remain throttled because the
+    // parent is still throttled.
+    childFrameElement->contentDocument()->view()->updateRenderThrottlingStatusForTesting();
+    EXPECT_TRUE(frameElement->contentDocument()->view()->canThrottleRendering());
+    EXPECT_TRUE(childFrameElement->contentDocument()->view()->canThrottleRendering());
+
+    // Updating throttling on the parent should unthrottle both frames.
+    frameElement->contentDocument()->view()->updateRenderThrottlingStatusForTesting();
+    EXPECT_FALSE(frameElement->contentDocument()->view()->canThrottleRendering());
+    EXPECT_FALSE(childFrameElement->contentDocument()->view()->canThrottleRendering());
 }
 
 TEST_F(FrameThrottlingTest, SkipPaintingLayersInThrottledFrames)
 {
     webView().settings()->setAcceleratedCompositingEnabled(true);
     webView().settings()->setPreferCompositingToLCDTextEnabled(true);
 
     SimRequest mainResource("https://example.com/", "text/html");
     SimRequest frameResource("https://example.com/iframe.html", "text/html");
 
@@ skipping 56 matching lines @@
     localFrame->script().executeScriptInMainWorld(
         "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");
     compositeFrame();
 }
 
 } // namespace blink