Reland “De-obfuscate X-Client-Data header values in Network tab”

Reland of: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2316062

Screenshot: https://i.imgur.com/LJHFIp9.png
Note that the screenshot shows this as a response header instead of a
request header, since that was easier to test. In real-world scenarios
it would be a request header instead, but the UI looks the same.

CL preparing the ClientVariationsParser for use in the DevTools UI:
https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2316065

[email protected],[email protected],[email protected],[email protected]

Bug: chromium:1103854
Change-Id: I6b959a1d57bcbc84f8571257a88fcbec805bf330
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2318257
Reviewed-by: Mathias Bynens <[email protected]>
Reviewed-by: Ilya Sherman <[email protected]>
Reviewed-by: Paul Lewis <[email protected]>
Commit-Queue: Mathias Bynens <[email protected]>
diff --git a/all_devtools_files.gni b/all_devtools_files.gni
index 6e4ba5a..78ceb6c 100644
--- a/all_devtools_files.gni
+++ b/all_devtools_files.gni
@@ -49,6 +49,7 @@
   "front_end/changes/changesSidebar.css",
   "front_end/changes/changesView.css",
   "front_end/changes/module.json",
+  "front_end/client_variations/module.json",
   "front_end/cm_headless/module.json",
   "front_end/cm_modes/module.json",
   "front_end/cm/codemirror.css",