Remove RenderProcessHost::is_extension_process

content/common/content_switches.cc

Index: content/common/content_switches.cc
diff --git a/content/common/content_switches.cc b/content/common/content_switches.cc
index 52d036257ad63a2c39c811400ba1256bdb13c097..6ac234dfce2467ed15119704d6f936a358791729 100644
--- a/content/common/content_switches.cc
+++ b/content/common/content_switches.cc
@@ -256,9 +256,6 @@ const char kExperimentalLocationFeatures[]  = "experimental-location-features";
 // Load NPAPI plugins from the specified directory.
 const char kExtraPluginDir[]                = "extra-plugin-dir";
 
-// Causes the process to run as an extension subprocess.
-const char kExtensionProcess[]              = "extension";
-
 // Some field tests may rendomized in the browser, and the randomly selected
 // outcome needs to be propagated to the renderer.  For instance, this is used
 // to modify histograms recorded in the renderer, or to get the renderer to