[Mac] Set CFBundleDocumentTypes for PDF in the Info.plist directly.

chrome/chrome_exe.gypi

Index: chrome/chrome_exe.gypi
diff --git a/chrome/chrome_exe.gypi b/chrome/chrome_exe.gypi
index 2ec9dca505f86eb5fab3134788d78a75bf3f3f1d..56eda731589220d04e9c3ad538fc2120082b31ea 100644
--- a/chrome/chrome_exe.gypi
+++ b/chrome/chrome_exe.gypi
@@ -360,15 +360,12 @@
               # application reads Keystone keys from this plist and not the
               # framework's, and the ticket will reference this Info.plist to
               # determine the tag of the installed product.  Use --scm=1 to
-              # include SCM information.  The --pdf flag controls whether
-              # to insert PDF as a supported type identifier that can be
-              # opened.
+              # include SCM information.
               'postbuild_name': 'Tweak Info.plist',
               'action': ['<(tweak_info_plist_path)',
                          '--breakpad=0',
                          '--keystone=<(mac_keystone)',
                          '--scm=1',
-                         '--pdf=1',
                          '--bundle_id=<(mac_bundle_id)'],
             },
             {