Convert --enable-md-history to a feature flag.

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 fd0af20aa539bfd3fdd50da345b7a659a2794e70..75be4b64ede15f882b5319601d15b8a35c8a39bc 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -426,9 +426,6 @@ const char kEnableFastUnload[] = "enable-fast-unload";
 // Enables the Material Design version of chrome://extensions.
 const char kEnableMaterialDesignExtensions[] = "enable-md-extensions";
 
-// Enables the Material Design version of chrome://history.
-const char kEnableMaterialDesignHistory[] = "enable-md-history";
-
 // Enables the Material Design policy page at chrome://md-policy.
 const char kEnableMaterialDesignPolicyPage[]  = "enable-md-policy-page";
 
@@ -1349,11 +1346,6 @@ bool MdExtensionsEnabled() {
       ::switches::kEnableMaterialDesignExtensions);
 }
 
-bool MdHistoryEnabled() {
-  return base::CommandLine::ForCurrentProcess()->HasSwitch(
-      ::switches::kEnableMaterialDesignHistory);
-}
-
 bool MdPolicyPageEnabled() {
   return base::CommandLine::ForCurrentProcess()->HasSwitch(
       ::switches::kEnableMaterialDesignPolicyPage);