Remove reference to Ganesh GL config

This is going away in https://skia-review.googlesource.com/892078
and PDFium does not use Skia's Ganesh backend so this is a no-op.

Bug: b:293490566
Change-Id: If75beed66b12b1808a1129fbf0344e1182bf1891
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/123710
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Kaylee Lubick <kjlubick@google.com>
Auto-Submit: Kaylee Lubick <kjlubick@google.com>
Reviewed-by: Lei Zhang <thestig@chromium.org>
diff --git a/skia/config/SkPdfiumUserConfig.h b/skia/config/SkPdfiumUserConfig.h
index 1d99c3c..5471322 100644
--- a/skia/config/SkPdfiumUserConfig.h
+++ b/skia/config/SkPdfiumUserConfig.h
@@ -212,7 +212,6 @@
 
 #define SK_ATTR_DEPRECATED SK_NOTHING_ARG1
 #define SK_ENABLE_INST_COUNT 0
-#define GR_GL_CUSTOM_SETUP_HEADER "GrGLConfig_chrome.h"
 
 // Blink layout tests are baselined to Clang optimizing through the UB in
 // SkDivBits.