Move tracing namespace from base::debug to base::trace_event.

cc/output/filter_operation.h

Index: cc/output/filter_operation.h
diff --git a/cc/output/filter_operation.h b/cc/output/filter_operation.h
index fc14cb1017ade130fe2cfa6c1bf7e70a4b92e825..9c0e0a313cd62367484fd7e5e5c1c1dea7b9ef17 100644
--- a/cc/output/filter_operation.h
+++ b/cc/output/filter_operation.h
@@ -16,11 +16,18 @@
 #include "ui/gfx/geometry/point.h"
 
 namespace base {
-namespace debug {
+namespace trace_event {
 class TracedValue;
 }
-class Value;
+
+// This is added temporarily. Once the renaming of namespace usages
+// accross all folders are done, this will be removed.
+// TODO(ssid): crrev.com/837303004
+namespace debug {
+using ::base::trace_event::TracedValue;
 }
+class Value;
+}  // namespace base
 
 namespace cc {