Split ppapi::PluginList from PepperPluginRegistry so that DRT could load pepper plugins.

content/common/content_switches.cc

Index: content/common/content_switches.cc
===================================================================
--- content/common/content_switches.cc	(revision 101488)
+++ content/common/content_switches.cc	(working copy)
@@ -360,9 +360,6 @@
 // defaults to "10.2.999.999".
 const char kPpapiFlashVersion[]             = "ppapi-flash-version";
 
-// Runs PPAPI (Pepper) plugins out-of-process.
-const char kPpapiOutOfProcess[]             = "ppapi-out-of-process";
-
 // Like kPluginLauncher for PPAPI plugins.
 const char kPpapiPluginLauncher[]           = "ppapi-plugin-launcher";
 
@@ -397,9 +394,6 @@
 // Causes the process to run as a profile import subprocess.
 const char kProfileImportProcess[]          = "profile-import";
 
-// Register Pepper plugins (see pepper_plugin_registry.cc for its format).
-const char kRegisterPepperPlugins[]         = "register-pepper-plugins";
-
 // Enable remote debug / automation shell on the specified port.
 const char kRemoteShellPort[]               = "remote-shell-port";