some preparations for mac native help

platform/platform-impl/src/com/intellij/ide/actions/HelpTopicsAction.java

@@ -15,13 +15,20 @@
  */
 package com.intellij.ide.actions;
 
+import com.apple.eawt.Application;
 import com.intellij.openapi.actionSystem.AnAction;
 import com.intellij.openapi.actionSystem.AnActionEvent;
 import com.intellij.openapi.help.HelpManager;
 import com.intellij.openapi.project.DumbAware;
+import com.intellij.openapi.util.SystemInfo;
+import com.intellij.openapi.util.registry.Registry;
 
 public class HelpTopicsAction extends AnAction implements DumbAware {
   public void actionPerformed(AnActionEvent e) {
-    HelpManager.getInstance().invokeHelp("top");
+    if (SystemInfo.isMac && Registry.is("ide.mac.show.native.help", false)) {
+      Application.getApplication().openHelpViewer();
+    } else {
+      HelpManager.getInstance().invokeHelp("top");
+    }
   }
 }

platform/platform-resources-en/src/misc/registry.properties

@@ -107,6 +107,7 @@ ide.mac.filechooser.native=true
 ide.mac.message.dialogs.as.sheets=true
 ide.mac.inplaceDialogMnemonicsFix=true
 ide.mac.hide.cursor.when.typing=false
+ide.mac.show.native.help=false
 
 debugger.valueTooltipAutoShow=true
 debugger.valueTooltipAutoShow.description=Auto show tooltip on mouse over