Add webview tracing bit

Change-Id: I82e54f5eeb2666a255e372fd3bfcc54c1b3d76a0
diff --git a/include/utils/Trace.h b/include/utils/Trace.h
index a2429c0..637c146 100644
--- a/include/utils/Trace.h
+++ b/include/utils/Trace.h
@@ -45,7 +45,8 @@
 #define ATRACE_TAG_GRAPHICS (1<<1)
 #define ATRACE_TAG_INPUT    (1<<2)
 #define ATRACE_TAG_VIEW     (1<<3)
-#define ATRACE_TAG_LAST     ATRACE_TAG_VIEW
+#define ATRACE_TAG_WEBVIEW  (1<<4)
+#define ATRACE_TAG_LAST     ATRACE_TAG_WEBVIEW
 
 #define ATRACE_TAG_VALID_MASK ((ATRACE_TAG_LAST - 1) | ATRACE_TAG_LAST)