Revert of Add builders for tracing event's structural arguments

cc/resources/raster_mode.cc

Index: cc/resources/raster_mode.cc
diff --git a/cc/resources/raster_mode.cc b/cc/resources/raster_mode.cc
index d67fdd850f445240fd81045fc8addb01842a23f3..5da8ee76e9b229677d05f5e9ad976a947ec19195 100644
--- a/cc/resources/raster_mode.cc
+++ b/cc/resources/raster_mode.cc
@@ -10,15 +10,18 @@
 
 namespace cc {
 
-std::string RasterModeToString(RasterMode raster_mode) {
+scoped_ptr<base::Value> RasterModeAsValue(RasterMode raster_mode) {
   switch (raster_mode) {
     case HIGH_QUALITY_RASTER_MODE:
-      return "HIGH_QUALITY_RASTER_MODE";
+      return scoped_ptr<base::Value>(
+          new base::StringValue("HIGH_QUALITY_RASTER_MODE"));
     case LOW_QUALITY_RASTER_MODE:
-      return "LOW_QUALITY_RASTER_MODE";
+      return scoped_ptr<base::Value>(
+          new base::StringValue("LOW_QUALITY_RASTER_MODE"));
     default:
       NOTREACHED() << "Unrecognized RasterMode value " << raster_mode;
-      return "<unknown RasterMode value>";
+      return scoped_ptr<base::Value>(
+          new base::StringValue("<unknown RasterMode value>"));
   }
 }