Add a telemetry measurement for property tree performance.

content/browser/gpu/compositor_util.h

Index: content/browser/gpu/compositor_util.h
diff --git a/content/browser/gpu/compositor_util.h b/content/browser/gpu/compositor_util.h
index 16dca45c45ad6f50fb522aab32067d3f8209e3f3..20862b3fa01d78ec46bd4f23578bc4649589ba8c 100644
--- a/content/browser/gpu/compositor_util.h
+++ b/content/browser/gpu/compositor_util.h
@@ -17,6 +17,10 @@ namespace content {
 // flags, or platform default).
 CONTENT_EXPORT bool IsPinchVirtualViewportEnabled();
 
+// Returns true if property tree verification is enabled (via flags or platform
+// defalt).
+CONTENT_EXPORT bool IsPropertyTreeVerificationEnabled();
+
 // Returns true if delegated-renderer is on (via flags, or platform default).
 CONTENT_EXPORT bool IsDelegatedRendererEnabled();