Convert enable_plugins to a buildflag header.

media/base/media_switches.cc

Index: media/base/media_switches.cc
diff --git a/media/base/media_switches.cc b/media/base/media_switches.cc
index 55d1ec765d377b4a48b2836425927df39cf60ed1..55572c764374f0a460b94251cf60412fbab447d5 100644
--- a/media/base/media_switches.cc
+++ b/media/base/media_switches.cc
@@ -4,6 +4,7 @@
 
 #include "build/build_config.h"
 #include "media/base/media_switches.h"
+#include "ppapi/features/features.h"
 
 namespace switches {
 
@@ -66,19 +67,19 @@ const char kWaveOutBuffers[] = "waveout-buffers";
 const char kUseCras[] = "use-cras";
 #endif
 
-#if !defined(OS_ANDROID) || defined(ENABLE_PLUGINS)
+#if !defined(OS_ANDROID) || BUILDFLAG(ENABLE_PLUGINS)
 // Use a media session for each tabs in a way that two tabs can't play on top of
 // each other. This is different from the Media Session API as it is enabling a
 // default behaviour for the browser. The allowed values are: "" (empty),
 // |kEnableDefaultMediaSessionDuckFlash|.
 const char kEnableDefaultMediaSession[] = "enable-default-media-session";
-#endif  // !defined(OS_ANDROID) || defined(ENABLE_PLUGINS)
+#endif  // !defined(OS_ANDROID) || BUILDFLAG(ENABLE_PLUGINS)
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
 // This value is used as an option for |kEnableDefaultMediaSession|. Flash will
 // be ducked when losing audio focus.
 const char kEnableDefaultMediaSessionDuckFlash[] = "duck-flash";
-#endif  // defined(ENABLE_PLUGINS)
+#endif  // BUILDFLAG(ENABLE_PLUGINS)
 
 // Use fake device for Media Stream to replace actual camera and microphone.
 const char kUseFakeDeviceForMediaStream[] = "use-fake-device-for-media-stream";