Use intersection observer to control frame throttling

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 13d13fee9221ed14ec03c2e1e5677a53c04f525c..e0f29b1427440a77d4e35fa2c1e83ab19058fb4c 100644
--- a/third_party/WebKit/Source/web/tests/FrameThrottlingTest.cpp
+++ b/third_party/WebKit/Source/web/tests/FrameThrottlingTest.cpp
@@ -450,7 +450,8 @@ TEST(RemoteFrameThrottlingTest, ThrottledLocalRoot)
     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());
@@ -462,10 +463,11 @@ TEST(RemoteFrameThrottlingTest, ThrottledLocalRoot)
 
     // 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();
 }
 
@@ -768,14 +770,31 @@ TEST_F(FrameThrottlingTest, ThrottleSubtreeAtomically)
     // 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)