Add switch (for cast_shell) to defer creation of GPU process.

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index 69d0941ea98aa3d3b59d69990e50d468da97f344..d460df7d418a2cddf8e1dfb0939bbbf5a98edce2 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -131,6 +131,9 @@ const char kDisableGpu[]                    = "disable-gpu";
 // Prevent the compositor from using its GPU implementation.
 const char kDisableGpuCompositing[]         = "disable-gpu-compositing";
 
+// Disable proactive early init of GPU process.
+const char kDisableGpuEarlyInit[]           = "disable-gpu-early-init";
+
 // Disable the limit on the number of times the GPU process may be restarted
 // This switch is intended only for tests.
 extern const char kDisableGpuProcessCrashLimit[] =