Create a command-line switch for enabling touch events.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 2fc46ef2720801af3f72a2963a24e4950245a503..95c866ef26570908056ade6d855d26199f44dc81 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -319,6 +319,9 @@ const char kEnableSyncThemes[]              = "enable-sync-themes";
 // Enable syncing browser typed urls.
 const char kEnableSyncTypedUrls[]           = "enable-sync-typed-urls";
 
+// Whether or not the touch events API is exposed.
+const char kEnableTouch[]                   = "enable-touch";
+
 // Whether the multiple profiles feature based on the user-data-dir flag is
 // enabled or not.
 const char kEnableUserDataDirProfiles[]     = "enable-udd-profiles";