Unify the three places that patch font loading for PDFium on Windows.

chrome/child/BUILD.gn

Index: chrome/child/BUILD.gn
diff --git a/chrome/plugin/BUILD.gn b/chrome/child/BUILD.gn
similarity index 61%
copy from chrome/plugin/BUILD.gn
copy to chrome/child/BUILD.gn
index 1da688a0741b86e45b2e3056bd13812ab31a3b1f..1b268f18b2ea6c814f23cea3133a02544453e6b5 100644
--- a/chrome/plugin/BUILD.gn
+++ b/chrome/child/BUILD.gn
@@ -2,18 +2,16 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-static_library("plugin") {
+static_library("child") {
   sources = [
-    "chrome_content_plugin_client.cc",
-    "chrome_content_plugin_client.h",
+    "pdf_child_init.cc",
+    "pdf_child_init.h",
   ]
 
   configs += [ "//build/config/compiler:wexit_time_destructors" ]
 
   deps = [
     "//base",
-    "//chrome:strings",
-    "//content/public/plugin",
-    "//gin",
+    "//content/public/child",
   ]
 }