Enable multiplanar for SPIRV fuzzers.

This CL updates the common fuzzer code to enable the multiplanar
extension for the SPIR-V backend.

Bug: chromium:1427801
Change-Id: Ie03d3e10f7831ca851aa11c00cbac0aa474ccabb
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/126920
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
diff --git a/src/tint/fuzzers/tint_common_fuzzer.cc b/src/tint/fuzzers/tint_common_fuzzer.cc
index 9813cfc..6be9b98 100644
--- a/src/tint/fuzzers/tint_common_fuzzer.cc
+++ b/src/tint/fuzzers/tint_common_fuzzer.cc
@@ -263,7 +263,8 @@
 
     // For the generates which use MultiPlanar, make sure the configuration options are provided so
     // that the transformer will execute.
-    if (output_ == OutputFormat::kMSL || output_ == OutputFormat::kHLSL) {
+    if (output_ == OutputFormat::kMSL || output_ == OutputFormat::kHLSL ||
+        output_ == OutputFormat::kSpv) {
         // Gather external texture binding information
         // Collect next valid binding number per group
         std::unordered_map<uint32_t, uint32_t> group_to_next_binding_number;
@@ -299,6 +300,10 @@
                 options_hlsl_.external_texture_options.bindings_map = new_bindings_map;
                 break;
             }
+            case OutputFormat::kSpv: {
+                options_spirv_.external_texture_options.bindings_map = new_bindings_map;
+                break;
+            }
             default:
                 break;
         }