Move ENABLE_PEPPER_CDMS to a buildflag header.

chrome/renderer/pepper/pepper_uma_host.cc

Index: chrome/renderer/pepper/pepper_uma_host.cc
diff --git a/chrome/renderer/pepper/pepper_uma_host.cc b/chrome/renderer/pepper/pepper_uma_host.cc
index 417483843899d8ab22b9410f6d384025301814a6..a62f1e49abda626b9c05213dc452b4caf19b27be 100644
--- a/chrome/renderer/pepper/pepper_uma_host.cc
+++ b/chrome/renderer/pepper/pepper_uma_host.cc
@@ -23,6 +23,7 @@
 #include "ppapi/host/host_message_context.h"
 #include "ppapi/host/ppapi_host.h"
 #include "ppapi/proxy/ppapi_messages.h"
+#include "third_party/widevine/cdm/cdm_features.h"
 
 #include "widevine_cdm_version.h"  // In SHARED_INTERMEDIATE_DIR.
 
@@ -51,7 +52,7 @@ const char* const kWhitelistedHistogramPrefixes[] = {
 };
 
 const char* const kWhitelistedPluginBaseNames[] = {
-#if defined(WIDEVINE_CDM_AVAILABLE) && defined(ENABLE_PEPPER_CDMS)
+#if defined(WIDEVINE_CDM_AVAILABLE) && BUILDFLAG(ENABLE_PEPPER_CDMS)
     kWidevineCdmAdapterFileName,  // see http://crbug.com/368743
                                   // and http://crbug.com/410630
 #endif