Fix some nits in build configs.

Mostly to sort build rules.

Change-Id: I2ee4d24089f9e51b0a61b1f30b424f5f7aab7d0a
Reviewed-on: https://pdfium-review.googlesource.com/21730
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/pdfium.gni b/pdfium.gni
index f05623a..e48750e 100644
--- a/pdfium.gni
+++ b/pdfium.gni
@@ -33,11 +33,11 @@
   # If XFA, also support png codec. Ignored if not XFA.
   pdf_enable_xfa_tiff = true
 
-  # Build PDFium against skia (experimental) rather than agg. Use Skia to draw
+  # Build PDFium against Skia (experimental) rather than AGG. Use Skia to draw
   # everything.
   pdf_use_skia = pdf_use_skia_override
 
-  # Build PDFium against skia (experimental) rather than agg. Use Skia to draw
+  # Build PDFium against Skia (experimental) rather than AGG. Use Skia to draw
   # paths.
   pdf_use_skia_paths = pdf_use_skia_paths_override