Move ENABLE_PEPPER_CDMS to a buildflag header.

chrome/browser/plugins/plugin_info_message_filter.h

Index: chrome/browser/plugins/plugin_info_message_filter.h
diff --git a/chrome/browser/plugins/plugin_info_message_filter.h b/chrome/browser/plugins/plugin_info_message_filter.h
index d0d802623cdcacdacb5940908e5feffb93163ed7..3c3506b526877cf2edfb0f216fe3ebd7146475be 100644
--- a/chrome/browser/plugins/plugin_info_message_filter.h
+++ b/chrome/browser/plugins/plugin_info_message_filter.h
@@ -18,6 +18,7 @@
 #include "components/content_settings/core/common/content_settings.h"
 #include "components/prefs/pref_member.h"
 #include "content/public/browser/browser_message_filter.h"
+#include "ppapi/features/features.h"
 
 struct ChromeViewHostMsg_GetPluginInfo_Output;
 enum class ChromeViewHostMsg_GetPluginInfo_Status;
@@ -129,7 +130,7 @@ class PluginInfoMessageFilter : public content::BrowserMessageFilter {
       std::unique_ptr<PluginMetadata> plugin_metadata,
       IPC::Message* reply_msg);
 
-#if defined(ENABLE_PEPPER_CDMS)
+#if BUILDFLAG(ENABLE_PEPPER_CDMS)
   // Returns whether any internal plugin supporting |mime_type| is registered
   // and enabled. Does not determine whether the plugin can actually be
   // instantiated (e.g. whether it has all its dependencies).