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 b1be5b9616a1f3d976ac6b18292581f5f5dca6e8..d1614c8c440aa0caa85850c342ad0c3068290972 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";
 
@@ -1346,11 +1343,6 @@ bool MdExtensionsEnabled() {
       ::switches::kEnableMaterialDesignExtensions);
 }
 
-bool MdHistoryEnabled() {
-  return base::CommandLine::ForCurrentProcess()->HasSwitch(
-      ::switches::kEnableMaterialDesignHistory);
-}
-
 bool MdPolicyPageEnabled() {
   return base::CommandLine::ForCurrentProcess()->HasSwitch(
       ::switches::kEnableMaterialDesignPolicyPage);