Add option to open PDFs in system viewer to OS X and Linux.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index b28a53d8e03b49d6f39ccd41e364d9cf37f4d832..e3d6c68c5c0319db20b672ad4c5c4a3a965fd508 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1463,10 +1463,10 @@ const char kDownloadDefaultDirectory[] = "download.default_directory";
 // upgrade a unsafe location to a safe location.
 const char kDownloadDirUpgraded[] = "download.directory_upgrade";
 
-#if defined(OS_WIN)
-// Whether downloaded PDFs should be opened in Adobe Acrobat Reader.
-const char kOpenPdfDownloadInAdobeReader[] =
-    "download.open_pdf_in_adobe_reader";

[asanka, 2014/10/23 07:38:04]

This change has the effect of resetting the "Open in <...>" preference for PDFs.
I recall having to add migration code when this cropped up before so that users
who have explicitly set their preference won't notice any change in behavior.

[palmer, 2014/10/23 22:17:08]

Should leave the name the same for Windows? Or have both names, and make them
synonyms?

+#if defined(OS_WIN) || defined(OS_LINUX) || \
+    (defined(OS_MACOSX) && !defined(OS_IOS))
+const char kOpenPdfDownloadInSystemReader[] =
+    "download.open_pdf_in_system_reader";
 #endif
 
 // String which specifies where to save html files to by default.