Merge to XFA: Fix all relative includes to third_party.

- In non-standalone builds, use the provided jpeg library.
- Run gn format over all the GN files.
- Also roll DEPS for buildtools to c2f2598.
- And fix XFA's lack of #includes.

BUG=541704
R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1425153006 .

(cherry picked from commit 34bb6c58fe60206a08dc0a1f37b7cfe83e8c762c)

Review URL: https://codereview.chromium.org/1434543003 .
diff --git a/DEPS b/DEPS
index b6d7efa..22c9409 100644
--- a/DEPS
+++ b/DEPS
@@ -5,7 +5,7 @@
     "https://chromium.googlesource.com/external/gyp",
 
   "buildtools":
-    "https://chromium.googlesource.com/chromium/buildtools.git@46ce8cb60364e9e0b21a81136c7debdddfd063a8",
+    "https://chromium.googlesource.com/chromium/buildtools.git@c2f259809d5ede3275df5ea0842f0431990c4f98",
 
   "testing/corpus":
      "https://pdfium.googlesource.com/pdfium_tests@45f88c6914fcac26ad930bb0ebbfa468c21db0a5",