TraceProcessor: restrict CORS headers to ui.perfetto.dev

Restrict CORS headers of trace_processor --httpd to
ui.perfetto.dev and localhost:10000.
This is to prevent that a malicious site tries to fetch() and
interact with a local trace processor instance.

Test: manual with both ui.perfetto.dev and localhost:10000
Change-Id: Icbbf530b5f3c8e6a4bc138804d43ca4580a7d668
diff --git a/CHANGELOG b/CHANGELOG
index ccb4b8d..be08930 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -2,7 +2,8 @@
   Tracing service and probes:
     *
   Trace Processor:
-    *
+    * Changed CORS headers of --httpd mode to allow only https://ui.perfetto.dev
+      and http://localhost:10000. This affects only CORS-aware browser clients.
   UI:
     * Fixed ADB connection issues ("unable to reset device") on Windows and Mac.
   SDK: