Add --enable-show-modal-dialog to chrome

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 0d96783dfcea4680981c75be25c218ad366915da..035979ced581b0e27c6bdfa7a38f8174e660c18c 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -600,6 +600,10 @@ const char kEnableSearchButtonInOmniboxForStrOrIip[] =
 // Enables using bubbles for session restore request instead of infobars.
 const char kEnableSessionCrashedBubble[] = "enable-session-crashed-bubble";
 
+// Enables the deprecated window.showModalDialog API. This is slated for
+// removal.
+const char kEnableShowModalDialog[] = "enable-show-modal-dialog";
+
 // Enable or disable settings in a separate browser window per profile
 // (see SettingsWindowEnabled() below).
 const char kEnableSettingsWindow[]           = "enable-settings-window";