Add absl/hash/hash.h to quiche_string_view.h.

PiperOrigin-RevId: 363946238
Change-Id: Ied4882dc663806d93d6a10b42e23ba119d6fab1c
diff --git a/common/platform/api/quiche_string_view.h b/common/platform/api/quiche_string_view.h
index 39714d4..3fa7a21 100644
--- a/common/platform/api/quiche_string_view.h
+++ b/common/platform/api/quiche_string_view.h
@@ -7,9 +7,12 @@
 
 // Chromium bans this include in net code except for QUICHE, which is a separate
 // compilation unit.  absl::string_view is used outside QUICHE in Chromium where
-// it is necessary to use the QUICHE API.  This header file allows Chromium code
-// to include string_view.h where absolutely necessary.
+// it is necessary to use the QUICHE API.  absl::Hash is used in
+// net/net/spdy/platform/impl/spdy_string_utils_impl.h in Chromium.  This header
+// file allows Chromium code to include string_view.h and hash.h where
+// absolutely necessary.
 
+#include "absl/hash/hash.h"
 #include "absl/strings/string_view.h"
 
 #endif  // QUICHE_COMMON_PLATFORM_API_QUICHE_STRING_VIEW_H_