Convert enable_plugins to a buildflag header.

content/renderer/render_frame_impl.h

Index: content/renderer/render_frame_impl.h
diff --git a/content/renderer/render_frame_impl.h b/content/renderer/render_frame_impl.h
index 8080771e160b08ac3edffda6bde22f5cd6a3e151..6aad5a6002069007a2890d53c37a3335a2ffeb9a 100644
--- a/content/renderer/render_frame_impl.h
+++ b/content/renderer/render_frame_impl.h
@@ -46,6 +46,7 @@
 #include "media/mojo/interfaces/remoting.mojom.h"
 #include "mojo/public/cpp/bindings/associated_binding.h"
 #include "mojo/public/cpp/bindings/binding.h"
+#include "ppapi/features/features.h"
 #include "services/service_manager/public/interfaces/connector.mojom.h"
 #include "services/service_manager/public/interfaces/interface_provider.mojom.h"
 #include "third_party/WebKit/public/platform/WebEffectiveConnectionType.h"
@@ -64,7 +65,7 @@
 #include "ui/gfx/range/range.h"
 #include "url/gurl.h"
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
 #include "content/renderer/pepper/plugin_power_saver_helper.h"
 #endif
 
@@ -311,7 +312,7 @@ class CONTENT_EXPORT RenderFrameImpl
   // Called when the widget receives a mouse event.
   void RenderWidgetWillHandleMouseEvent();
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   // Get/set the plugin which will be used to handle document find requests.
   void set_plugin_find_handler(PepperPluginInstanceImpl* plugin) {
     plugin_find_handler_ = plugin;
@@ -374,7 +375,7 @@ class CONTENT_EXPORT RenderFrameImpl
                        int relative_cursor_pos);
   void OnImeFinishComposingText(bool keep_selection);
 
-#endif  // defined(ENABLE_PLUGINS)
+#endif  // BUILDFLAG(ENABLE_PLUGINS)
 
   // May return NULL in some cases, especially if userMediaClient() returns
   // NULL.
@@ -418,7 +419,7 @@ class CONTENT_EXPORT RenderFrameImpl
   service_manager::InterfaceProvider* GetRemoteInterfaces() override;
   AssociatedInterfaceRegistry* GetAssociatedInterfaceRegistry() override;
   AssociatedInterfaceProvider* GetRemoteAssociatedInterfaces() override;
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   void RegisterPeripheralPlugin(
       const url::Origin& content_origin,
       const base::Closure& unthrottle_callback) override;
@@ -682,7 +683,7 @@ class CONTENT_EXPORT RenderFrameImpl
 
   // Plugin-related functions --------------------------------------------------
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   PepperPluginInstanceImpl* focused_pepper_plugin() {
     return focused_pepper_plugin_;
   }
@@ -1040,7 +1041,7 @@ class CONTENT_EXPORT RenderFrameImpl
   media::CdmFactory* GetCdmFactory();
   media::DecoderFactory* GetDecoderFactory();
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   void HandlePepperImeCommit(const base::string16& text);
 #endif  // ENABLE_PLUGINS
 
@@ -1143,7 +1144,7 @@ class CONTENT_EXPORT RenderFrameImpl
   // be reported to the browser process via SendUpdateState.
   blink::WebHistoryItem current_history_item_;
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   // Current text input composition text. Empty if no composition is in
   // progress.
   base::string16 pepper_composition_text_;
@@ -1311,7 +1312,7 @@ class CONTENT_EXPORT RenderFrameImpl
   std::unique_ptr<FrameBlameContext> blame_context_;
 
   // Plugins -------------------------------------------------------------------
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   typedef std::set<PepperPluginInstanceImpl*> PepperPluginSet;
   PepperPluginSet active_pepper_instances_;