Load pdf component dynamically.

Ship pdf as dll library, electron only loads pdf.dll when calling print
API. In this way, the developer who don't need print feature can safe
remove the pdf.dll in saving their binary size.

atom/app/atom_main_delegate.cc

@@ -64,6 +64,12 @@ void AtomMainDelegate::PreSandboxStartup() {
   std::string process_type = command_line->GetSwitchValueASCII(
       switches::kProcessType);
 
+#if defined(OS_WIN)
+  if (process_type == switches::kUtilityProcess) {
+    AtomContentUtilityClient::PreSandboxStartup();
+  }
+#endif
+
   // Only append arguments for browser process.
   if (!process_type.empty())
     return;