Eliminate third_party/mojo/src from all targets' include paths

mojo/services/tracing/main.cc

Index: mojo/services/tracing/main.cc
diff --git a/mojo/services/tracing/main.cc b/mojo/services/tracing/main.cc
index 1810d1b27904b52ea9f5281936cca92e4045de77..a7875aa939138b41db92a0c8e50ce4a16b4d7af6 100644
--- a/mojo/services/tracing/main.cc
+++ b/mojo/services/tracing/main.cc
@@ -4,8 +4,8 @@
 
 #include "mojo/application/public/cpp/application_impl.h"
 #include "mojo/application/public/cpp/application_runner.h"
-#include "mojo/public/c/system/main.h"
 #include "mojo/services/tracing/tracing_app.h"
+#include "third_party/mojo/src/mojo/public/c/system/main.h"
 
 MojoResult MojoMain(MojoHandle shell_handle) {
   mojo::ApplicationRunner runner(new tracing::TracingApp);