Adding tracing to measure synthetic smooth scrolling correctness

content/browser/renderer_host/render_widget_host_view_base.cc

Index: content/browser/renderer_host/render_widget_host_view_base.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_base.cc b/content/browser/renderer_host/render_widget_host_view_base.cc
index 51e530aa858449aa9f525e4215f72f77d58540f9..42932ac5dd7d4f00e85e0003371e5a01e45a14f7 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.cc
+++ b/content/browser/renderer_host/render_widget_host_view_base.cc
@@ -4,6 +4,7 @@
 
 #include "content/browser/renderer_host/render_widget_host_view_base.h"
 
+#include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
@@ -460,6 +461,9 @@ class BasicMouseWheelSmoothScrollGesture
 
     pixels_scrolled_ += abs(event.deltaY);
 
+    TRACE_COUNTER_ID1("gpu", "smooth_scroll_by_pixels_scrolled", this,
+                      pixels_scrolled_);
+
     return true;
   }