Convert enable_plugins to a buildflag header.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index a6624392d098a089f7b85629ed64dcc6154385b9..319daf9e93ac0e6e1c635641741de2db525e2850 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -129,6 +129,7 @@
 #include "net/http/http_transaction_factory.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_context_getter.h"
+#include "ppapi/features/features.h"
 #include "services/service_manager/public/cpp/interface_provider.h"
 #include "third_party/WebKit/public/platform/WebSecurityStyle.h"
 #include "third_party/WebKit/public/web/WebSandboxFlags.h"
@@ -156,7 +157,7 @@
 #include "ui/aura/mus/mus_util.h"
 #endif
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
 #include "content/browser/media/session/pepper_playback_observer.h"
 #endif  // ENABLE_PLUGINS
 
@@ -464,7 +465,7 @@ WebContentsImpl::WebContentsImpl(BrowserContext* browser_context)
 #else
   media_web_contents_observer_.reset(new MediaWebContentsObserver(this));
 #endif
-#if defined (ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   pepper_playback_observer_.reset(new PepperPlaybackObserver(this));
 #endif
   loader_io_thread_notifier_.reset(new LoaderIOThreadNotifier(this));
@@ -549,7 +550,7 @@ WebContentsImpl::~WebContentsImpl() {
     }
   }
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   // Call this before WebContentsDestroyed() is broadcasted since
   // AudioFocusManager will be destroyed after that.
   pepper_playback_observer_.reset();
@@ -737,7 +738,7 @@ bool WebContentsImpl::OnMessageReceived(RenderViewHost* render_view_host,
     IPC_MESSAGE_HANDLER(FrameHostMsg_Find_Reply, OnFindReply)
     IPC_MESSAGE_HANDLER(ViewHostMsg_AppCacheAccessed, OnAppCacheAccessed)
     IPC_MESSAGE_HANDLER(ViewHostMsg_WebUISend, OnWebUISend)
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
     IPC_MESSAGE_HANDLER(FrameHostMsg_PepperInstanceCreated,
                         OnPepperInstanceCreated)
     IPC_MESSAGE_HANDLER(FrameHostMsg_PepperInstanceDeleted,
@@ -1608,7 +1609,7 @@ void WebContentsImpl::Init(const WebContents::CreateParams& params) {
   gfx::Size initial_size = params.initial_size;
   view_->CreateView(initial_size, params.context);
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
   plugin_content_origin_whitelist_.reset(
       new PluginContentOriginWhitelist(this));
 #endif
@@ -3753,7 +3754,7 @@ void WebContentsImpl::OnWebUISend(const GURL& source_url,
     delegate_->WebUISend(this, source_url, name, args);
 }
 
-#if defined(ENABLE_PLUGINS)
+#if BUILDFLAG(ENABLE_PLUGINS)
 void WebContentsImpl::OnPepperInstanceCreated(int32_t pp_instance) {
   for (auto& observer : observers_)
     observer.PepperInstanceCreated();
@@ -3818,7 +3819,7 @@ void WebContentsImpl::OnBrowserPluginMessage(RenderFrameHost* render_frame_host,
   CreateBrowserPluginEmbedderIfNecessary();
   browser_plugin_embedder_->OnMessageReceived(message, render_frame_host);
 }
-#endif  // defined(ENABLE_PLUGINS)
+#endif  // BUILDFLAG(ENABLE_PLUGINS)
 
 void WebContentsImpl::OnUpdateFaviconURL(
     const std::vector<FaviconURL>& candidates) {