Enable shared_dictionary for quality 3 and 4.

PiperOrigin-RevId: 767264145

c/enc/backward_references.c

diff --git a/c/enc/backward_references.c b/c/enc/backward_references.c
index 94fd704..805c001 100644
--- a/c/enc/backward_references.c
+++ b/c/enc/backward_references.c
@@ -133,6 +133,14 @@
 #define PREFIX() D
 #define ENABLE_COMPOUND_DICTIONARY 1
 
+#define HASHER() H3
+/* NOLINTNEXTLINE(build/include) */
+#include "backward_references_inc.h"
+#undef HASHER
+#define HASHER() H4
+/* NOLINTNEXTLINE(build/include) */
+#include "backward_references_inc.h"
+#undef HASHER
 #define HASHER() H5
 /* NOLINTNEXTLINE(build/include) */
 #include "backward_references_inc.h"
@@ -194,6 +202,8 @@
             literal_context_lut, params, hasher, dist_cache,        \
             last_insert_len, commands, num_commands, num_literals); \
         return;
+      CASE_(3)
+      CASE_(4)
       CASE_(5)
       CASE_(6)
 #if defined(BROTLI_MAX_SIMD_QUALITY)