Revert r192949 "Disable shader disk cache by default."

gpu/command_buffer/service/gpu_switches.cc

Index: gpu/command_buffer/service/gpu_switches.cc
diff --git a/gpu/command_buffer/service/gpu_switches.cc b/gpu/command_buffer/service/gpu_switches.cc
index 6a77db024583802e1c5ec28735bfcbc40f26ac9f..6d699ad628818cea64f5cdc23f447192b2e7a1b3 100644
--- a/gpu/command_buffer/service/gpu_switches.cc
+++ b/gpu/command_buffer/service/gpu_switches.cc
@@ -60,7 +60,7 @@ const char kGpuProgramCacheSizeKb[]         = "gpu-program-cache-size-kb";
 const char kTraceGL[]       = "trace-gl";
 
 // Disables the GPU shader on disk cache.
-const char kEnableGpuShaderDiskCache[]      = "enable-gpu-shader-disk-cache";
+const char kDisableGpuShaderDiskCache[]     = "disable-gpu-shader-disk-cache";
 
 const char* kGpuSwitches[] = {
   kCompileShaderAlwaysSucceeds,
@@ -79,7 +79,7 @@ const char* kGpuSwitches[] = {
   kGpuDriverBugWorkarounds,
   kGpuProgramCacheSizeKb,
   kTraceGL,
-  kEnableGpuShaderDiskCache,
+  kDisableGpuShaderDiskCache,
 };
 
 const int kNumGpuSwitches = arraysize(kGpuSwitches);