Fix PrePaint UMA when SlimmingPaintInvalidation is disabled

third_party/WebKit/Source/core/frame/FrameView.cpp

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index 93a42bb40dca6076bc944a1ef652c21933171a5a..2fa5b44f91196280926dc8957e3d66ed4cec667f 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -3028,7 +3028,6 @@ void FrameView::performScrollAnchoringAdjustments() {
 
 void FrameView::prePaint() {
   TRACE_EVENT0("blink", "FrameView::prePaint");
-  SCOPED_BLINK_UMA_HISTOGRAM_TIMER("Blink.PrePaint.UpdateTime");
 
   if (!m_paintController)
     m_paintController = PaintController::create();
@@ -3050,8 +3049,10 @@ void FrameView::prePaint() {
     }
   });
 
-  if (RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled())
+  if (RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled()) {
+    SCOPED_BLINK_UMA_HISTOGRAM_TIMER("Blink.PrePaint.UpdateTime");
     PrePaintTreeWalk(*m_geometryMapper).walk(*this);
+  }
 
   forAllNonThrottledFrameViews([](FrameView& frameView) {
     frameView.lifecycle().advanceTo(DocumentLifecycle::PrePaintClean);