Create a new disk_cache type, SHADER_CACHE.

net/base/cache_type.h

Index: net/base/cache_type.h
diff --git a/net/base/cache_type.h b/net/base/cache_type.h
index 08233891c15deefed3a378e054d052f8c1d232ef..a7a21dfe18ed81b53c27bf6a75e901592c002c52 100644
--- a/net/base/cache_type.h
+++ b/net/base/cache_type.h
@@ -12,7 +12,8 @@ enum CacheType {
   DISK_CACHE,  // Disk is used as the backing storage.
   MEMORY_CACHE,  // Data is stored only in memory.
   MEDIA_CACHE,  // Optimized to handle media files.
-  APP_CACHE  // Backing store for an AppCache.
+  APP_CACHE,  // Backing store for an AppCache.
+  SHADER_CACHE  // Backing store for the GL shader cache.
 };
 
 }  // namespace disk_cache