Remove the kDisableGpuProcessPrelaunch flag and disable tests.

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 f9b674648b8e788a77a4982f0f6a0b2f435ff399..8acdc462fc9da7e20e44904b168c238301f400c0 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -197,10 +197,6 @@ const char kDisableGpuCompositing[]         = "disable-gpu-compositing";
 extern const char kDisableGpuProcessCrashLimit[] =
     "disable-gpu-process-crash-limit";
 
-// Do not launch the GPU process shortly after browser process launch. Instead
-// launch it when it is first needed.
-const char kDisableGpuProcessPrelaunch[]    = "disable-gpu-process-prelaunch";
-
 // Disable GPU rasterization, i.e. rasterize on the CPU only.
 // Overrides the kEnableGpuRasterization and kForceGpuRasterization flags.
 const char kDisableGpuRasterization[]       = "disable-gpu-rasterization";