Bug 999631 - Disable startup cache via a dedicated flag. r=mshal

configure.in

@@ -7446,6 +7446,23 @@ if test -n "$MOZ_REFLOW_PERF"; then
     AC_DEFINE(MOZ_REFLOW_PERF)
 fi
 
+dnl ========================================================
+dnl = Offer a way to disable the startup cache
+dnl ========================================================
+MOZ_DISABLE_STARTUPCACHE=
+
+MOZ_ARG_DISABLE_BOOL(startupcache,
+[  --disable-startupcache          Disable startup cache ],
+    MOZ_DISABLE_STARTUPCACHE=1,
+    MOZ_DISABLE_STARTUPCACHE=)
+
+dnl bug 988880: disable startup cache on b2g
+if test -n "$MOZ_B2G"; then
+  MOZ_DISABLE_STARTUPCACHE=1
+fi
+
+AC_SUBST(MOZ_DISABLE_STARTUPCACHE)
+
 dnl ========================================================
 dnl = Enable Radio Interface for B2G (Gonk usually)
 dnl ========================================================

startupcache/StartupCache.cpp

@@ -93,7 +93,7 @@ StartupCache::GetSingleton()
     if (XRE_GetProcessType() != GeckoProcessType_Default) {
       return nullptr;
     }
-#ifdef MOZ_B2G
+#ifdef MOZ_DISABLE_STARTUP_CACHE
     return nullptr;
 #endif
 

toolkit/mozapps/installer/packager.py

@@ -376,7 +376,8 @@ def main():
                 f.preload(log[key])
 
     # Fill startup cache
-    if isinstance(formatter, OmniJarFormatter) and launcher.can_launch():
+    if isinstance(formatter, OmniJarFormatter) and launcher.can_launch() \
+      and buildconfig.substs['MOZ_DISABLE_STARTUPCACHE'] != '1':
         if buildconfig.substs['LIBXUL_SDK']:
             gre_path = mozpack.path.join(buildconfig.substs['LIBXUL_DIST'],
                                          'bin')