Don't strip main from the browser or helper app executables

chrome/app/chrome_exe_main.mm

Index: chrome/app/chrome_exe_main.mm
===================================================================
--- chrome/app/chrome_exe_main.mm	(revision 42807)
+++ chrome/app/chrome_exe_main.mm	(working copy)
@@ -11,6 +11,7 @@
 int ChromeMain(int argc, char** argv);
 }
 
+__attribute__((visibility("default")))
 int main(int argc, char* argv[]) {
   int rv = ChromeMain(argc, argv);