Begin tracking why layout is invalidated

LayoutTests/inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node-expected.txt

Index: LayoutTests/inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node-expected.txt
diff --git a/LayoutTests/inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node-expected.txt b/LayoutTests/inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node-expected.txt
index f4b10ba0ace5579638d23a82dd166166e9a34b94..f8d1ef0bbc7c0749ce8650baf38fc26b650992bb 100644
--- a/LayoutTests/inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node-expected.txt
+++ b/LayoutTests/inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node-expected.txt
@@ -27,7 +27,7 @@ paint invalidations[
         type : "StyleRecalcInvalidationTracking"
     }
     {
-        cause : {reason: Layout forced, stackTrace: .../inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node.html:13}
+        cause : {reason: Style changed, stackTrace: .../inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node.html:13}
         changedAttribute : undefined
         changedClass : undefined
         changedId : undefined
@@ -38,7 +38,7 @@ paint invalidations[
         type : "LayoutInvalidationTracking"
     }
     {
-        cause : {reason: Layout forced, stackTrace: .../inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node.html:14}
+        cause : {reason: DOM changed, stackTrace: .../inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node.html:14}
         changedAttribute : undefined
         changedClass : undefined
         changedId : undefined
@@ -49,7 +49,7 @@ paint invalidations[
         type : "LayoutInvalidationTracking"
     }
     {
-        cause : {reason: Layout forced, stackTrace: .../inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node.html:14}
+        cause : {reason: DOM changed, stackTrace: .../inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node.html:14}
         changedAttribute : undefined
         changedClass : undefined
         changedId : undefined
@@ -75,7 +75,7 @@ second paint invalidations[
         type : "StyleRecalcInvalidationTracking"
     }
     {
-        cause : {reason: Layout forced, stackTrace: .../inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node.html:25}
+        cause : {reason: Style changed, stackTrace: .../inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node.html:25}
         changedAttribute : undefined
         changedClass : undefined
         changedId : undefined
@@ -86,7 +86,7 @@ second paint invalidations[
         type : "LayoutInvalidationTracking"
     }
     {
-        cause : {reason: Layout forced, stackTrace: .../inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node.html:26}
+        cause : {reason: DOM changed, stackTrace: .../inspector/tracing/timeline-paint-with-layout-invalidations-on-deleted-node.html:26}
         changedAttribute : undefined
         changedClass : undefined
         changedId : undefined