Merge to XFA: Update bundled freetype to 2.6.1

Also adds a README.pdfium and 0000-include.patch that
details the local modifications made.

Also rolls testing/corpus to 45f88c6914fcac26ad930bb0ebbfa468c21db0a5
which includes regenerated corpus expectations.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1413673003 .

(cherry picked from commit 87ee069d05ca06f60d6cfacd9e426739d8f2053d)

Review URL: https://codereview.chromium.org/1416993005 .
diff --git a/third_party/BUILD.gn b/third_party/BUILD.gn
index 7c31e56..7f27327 100644
--- a/third_party/BUILD.gn
+++ b/third_party/BUILD.gn
@@ -49,25 +49,27 @@
   ]
   defines = [ "FT2_BUILD_LIBRARY" ]
   sources = [
-    "freetype/include/freetype.h",
+    "freetype/include/freetype/freetype.h",
+    "freetype/include/freetype/ftmm.h",
+    "freetype/include/freetype/ftotval.h",
+    "freetype/include/freetype/ftoutln.h",
+    "freetype/include/freetype/internal/ftobjs.h",
+    "freetype/include/freetype/internal/ftstream.h",
+    "freetype/include/freetype/internal/tttypes.h",
+    "freetype/include/freetype/tttables.h",
     "freetype/include/ft2build.h",
-    "freetype/include/ftmm.h",
-    "freetype/include/ftotval.h",
-    "freetype/include/ftoutln.h",
-    "freetype/include/tttables.h",
-    "freetype/include/internal/ftobjs.h",
-    "freetype/include/internal/ftstream.h",
-    "freetype/include/internal/tttypes.h",
-    "freetype/src/cff/cffobjs.h",
-    "freetype/src/cff/cfftypes.h",
-    "freetype/src/cff/cff.c",
     "freetype/src/base/ftbase.c",
+    "freetype/src/base/ftbase.h",
     "freetype/src/base/ftbitmap.c",
     "freetype/src/base/ftglyph.c",
     "freetype/src/base/ftinit.c",
     "freetype/src/base/ftlcdfil.c",
     "freetype/src/base/ftmm.c",
     "freetype/src/base/ftsystem.c",
+    "freetype/src/cff/cff.c",
+    "freetype/src/cff/cffobjs.h",
+    "freetype/src/cff/cfftypes.h",
+    "freetype/src/cid/type1cid.c",
     "freetype/src/psaux/psaux.c",
     "freetype/src/pshinter/pshinter.c",
     "freetype/src/psnames/psmodule.c",
@@ -76,7 +78,6 @@
     "freetype/src/smooth/smooth.c",
     "freetype/src/truetype/truetype.c",
     "freetype/src/type1/type1.c",
-    "freetype/src/cid/type1cid.c",
   ]
 }