Disable under-invalidation checking in two video paint invalidation tests

third_party/WebKit/LayoutTests/paint/invalidation/video-mute-repaint.html

Index: third_party/WebKit/LayoutTests/paint/invalidation/video-mute-repaint.html
diff --git a/third_party/WebKit/LayoutTests/paint/invalidation/video-mute-repaint.html b/third_party/WebKit/LayoutTests/paint/invalidation/video-mute-repaint.html
index 94e8f73a9ca0ce5b701bc974ee2884234fea62ef..4b825c8f71c66563bcd1683ca6971debd6cb4da3 100644
--- a/third_party/WebKit/LayoutTests/paint/invalidation/video-mute-repaint.html
+++ b/third_party/WebKit/LayoutTests/paint/invalidation/video-mute-repaint.html
@@ -9,6 +9,11 @@
 </video>
 
 <script>
+    // Disable under-invalidation checking because we allow short period of
+    // under-invalidation of buffered ranges.
+    if (window.internals)
+        internals.runtimeFlags.paintUnderInvalidationCheckingEnabled = false;
+
     window.testIsAsync = true;
 
     var video = document.getElementById("v");