Move enable extensions define to a build flag.

chrome/browser/memory_details.cc

Index: chrome/browser/memory_details.cc
diff --git a/chrome/browser/memory_details.cc b/chrome/browser/memory_details.cc
index 48ecf06f68506085da837fc22e850267f7ed6cdd..0da07a251f998fc19f0037e94486bf82aa98501a 100644
--- a/chrome/browser/memory_details.cc
+++ b/chrome/browser/memory_details.cc
@@ -30,13 +30,14 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/bindings_policy.h"
 #include "content/public/common/content_constants.h"
+#include "extensions/features/features.h"
 #include "ui/base/l10n/l10n_util.h"
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID)
 #include "content/public/browser/zygote_host_linux.h"
 #endif
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/process_manager.h"
 #include "extensions/browser/process_map.h"
@@ -51,7 +52,7 @@ using content::NavigationEntry;
 using content::RenderViewHost;
 using content::RenderWidgetHost;
 using content::WebContents;
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
 using extensions::Extension;
 #endif
 
@@ -241,7 +242,7 @@ void MemoryDetails::CollectChildInfoOnUIThread() {
       render_process_host = widgets_by_pid[process.pid].front()->GetProcess();
     }
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
     // Determine if this is an extension process.
     bool process_is_for_extensions = false;
     if (render_process_host) {
@@ -303,7 +304,7 @@ void MemoryDetails::CollectChildInfoOnUIThread() {
         process.renderer_type = ProcessMemoryInformation::RENDERER_CHROME;
       }
 
-#if defined(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_EXTENSIONS)
       if (!is_webui && process_is_for_extensions) {
         const Extension* extension =
             extensions::ExtensionRegistry::Get(