Move hash.h/cc from net/disk_cache to base.

net/disk_cache/storage_block-inl.h

Index: net/disk_cache/storage_block-inl.h
diff --git a/net/disk_cache/storage_block-inl.h b/net/disk_cache/storage_block-inl.h
index cc0b2aa0cea91c5101f8d145cebc13bad5ebdff5..098cd74afa7e550a8379dce7b631afb8609408fb 100644
--- a/net/disk_cache/storage_block-inl.h
+++ b/net/disk_cache/storage_block-inl.h
@@ -7,8 +7,8 @@
 
 #include "net/disk_cache/storage_block.h"
 
+#include "base/hash.h"
 #include "base/logging.h"
-#include "net/disk_cache/hash.h"
 #include "net/disk_cache/trace.h"
 
 namespace disk_cache {
@@ -167,7 +167,7 @@ template<typename T> void StorageBlock<T>::DeleteData() {
 }
 
 template<typename T> uint32 StorageBlock<T>::CalculateHash() const {
-  return Hash(reinterpret_cast<char*>(data_), offsetof(T, self_hash));
+  return base::Hash(reinterpret_cast<char*>(data_), offsetof(T, self_hash));
 }
 
 }  // namespace disk_cache