Add nogncheck to conditional includes.

Conditional includes need a nogncheck comment to prevent gn from
complaining if they are present but not available. In this particular
case Chromium's //skia:skia build currently does not know about any of
Skia's public headers. When adding these headers to the build, gn
complains about these includes in pdfium since the Skia headers have
become known to gn but pdfium does not depend on Skia. Unfortunately, gn
does not understand that pdfium is conditionally including these headers
and will not actually include them in the Chromium build.

Change-Id: I7a2b08fcd60aa49d2cdc23b1e7ad35f6e3e0fabb
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/71610
Commit-Queue: Ben Wagner <bungeman@google.com>
Auto-Submit: Ben Wagner <bungeman@google.com>
Reviewed-by: Lei Zhang <thestig@chromium.org>
diff --git a/core/fxge/cfx_glyphcache.cpp b/core/fxge/cfx_glyphcache.cpp
index 0e7e6b5..10e9428 100644
--- a/core/fxge/cfx_glyphcache.cpp
+++ b/core/fxge/cfx_glyphcache.cpp
@@ -25,12 +25,12 @@
 #include "third_party/base/numerics/safe_math.h"
 
 #if defined _SKIA_SUPPORT_ || _SKIA_SUPPORT_PATHS_
-#include "third_party/skia/include/core/SkStream.h"
-#include "third_party/skia/include/core/SkTypeface.h"
+#include "third_party/skia/include/core/SkStream.h"  // nogncheck
+#include "third_party/skia/include/core/SkTypeface.h"  // nogncheck
 
 #if defined(OS_WIN)
-#include "third_party/skia/include/core/SkFontMgr.h"
-#include "third_party/skia/include/ports/SkFontMgr_empty.h"
+#include "third_party/skia/include/core/SkFontMgr.h"  // nogncheck
+#include "third_party/skia/include/ports/SkFontMgr_empty.h"  // nogncheck
 #endif
 #endif
 
diff --git a/core/fxge/cfx_glyphcache.h b/core/fxge/cfx_glyphcache.h
index d8305c7..a969e0c 100644
--- a/core/fxge/cfx_glyphcache.h
+++ b/core/fxge/cfx_glyphcache.h
@@ -18,7 +18,7 @@
 
 #if defined _SKIA_SUPPORT_ || _SKIA_SUPPORT_PATHS_
 #include "core/fxge/fx_font.h"
-#include "third_party/skia/include/core/SkTypeface.h"
+#include "third_party/skia/include/core/SkTypeface.h"  // nogncheck
 #endif
 
 class CFX_Font;
diff --git a/core/fxge/cfx_renderdevice.cpp b/core/fxge/cfx_renderdevice.cpp
index f6be878..2f1546a 100644
--- a/core/fxge/cfx_renderdevice.cpp
+++ b/core/fxge/cfx_renderdevice.cpp
@@ -31,7 +31,7 @@
 #include "third_party/base/span.h"
 
 #if defined _SKIA_SUPPORT_ || defined _SKIA_SUPPORT_PATHS_
-#include "third_party/skia/include/core/SkTypes.h"
+#include "third_party/skia/include/core/SkTypes.h"  // nogncheck
 #endif
 
 namespace {