Merge to XFA: Correct unexpected hinting fonts

If the font is 'tricky', it needs to be hinted by default according to the description in freetype.

BUG=490814
TBR=jun_fang@foxitsoftware.com

Original Review URL: https://codereview.chromium.org/1170313003.

Review URL: https://codereview.chromium.org/1175243008.
diff --git a/DEPS b/DEPS
index 59e39a4..af90a67 100644
--- a/DEPS
+++ b/DEPS
@@ -6,7 +6,7 @@
     "https://chromium.googlesource.com/chromium/buildtools.git@46ce8cb60364e9e0b21a81136c7debdddfd063a8",
 
   "testing/corpus":
-     "https://pdfium.googlesource.com/pdfium_tests@73e1d0c915fe574a470fcbc76dd36246ac9fec45",
+     "https://pdfium.googlesource.com/pdfium_tests@4b9a1d593e5a101d034a4f1195174a22c179a42d",
 
   "testing/gmock":
      "https://chromium.googlesource.com/external/googlemock.git@29763965ab52f24565299976b936d1265cb6a271",