XFA: Add missing libtiff file from commit 9c2c87d1c744.

TBR=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1571523002 .
diff --git a/third_party/BUILD.gn b/third_party/BUILD.gn
index ed8037b..0ad92ab 100644
--- a/third_party/BUILD.gn
+++ b/third_party/BUILD.gn
@@ -306,6 +306,7 @@
     ]
     sources = [
       "libtiff/tiffiop.h",
+      "libtiff/tiffvers.h",
       "libtiff/tif_aux.c",
       "libtiff/tif_close.c",
       "libtiff/tif_codec.c",
diff --git a/third_party/libtiff/tiffvers.h b/third_party/libtiff/tiffvers.h
new file mode 100644
index 0000000..e965814
--- /dev/null
+++ b/third_party/libtiff/tiffvers.h
@@ -0,0 +1,9 @@
+#define TIFFLIB_VERSION_STR "LIBTIFF, Version 4.0.6\nCopyright (c) 1988-1996 Sam Leffler\nCopyright (c) 1991-1996 Silicon Graphics, Inc."
+/*
+ * This define can be used in code that requires
+ * compilation-related definitions specific to a
+ * version or versions of the library.  Runtime
+ * version checking should be done based on the
+ * string returned by TIFFGetVersion.
+ */
+#define TIFFLIB_VERSION 20150912
diff --git a/third_party/third_party.gyp b/third_party/third_party.gyp
index b57009c..54b6aa3 100644
--- a/third_party/third_party.gyp
+++ b/third_party/third_party.gyp
@@ -330,6 +330,7 @@
           'type': 'static_library',
           'sources': [
             'libtiff/tiffiop.h',
+            'libtiff/tiffvers.h',
             'libtiff/tif_aux.c',
             'libtiff/tif_close.c',
             'libtiff/tif_codec.c',