Roll DirectX Shader Compiler from 8b406b5717ca to 2a6bacd8712b (3 revisions)

https://chromium.googlesource.com/external/github.com/microsoft/DirectXShaderCompiler.git/+log/8b406b5717ca..2a6bacd8712b

2025-05-15 stevenperron@google.com [SPIRV] Treat vk::Spirv*Type as opaque when reconstructing (#7454)
2025-05-15 stevenperron@google.com [SPIRV] Allow decoration attributes on fields. (#7453)
2025-05-15 stevenperron@google.com [SPIRV] Cast derivative opts to 32-bits. (#7445)

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/directx-shader-compiler-dawn
Please CC rharrison@google.com,webgpu-developers@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in DirectX Shader Compiler: https://github.com/microsoft/DirectXShaderCompiler/issues/new/choose
To file a bug in Dawn: https://bugs.chromium.org/p/dawn/issues/entry

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Bug: None
Tbr: rharrison@google.com
Change-Id: Idf2e874100b8b146e7fe7ef8c6a3183e9b9007de
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/242614
Commit-Queue: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>
Bot-Commit: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>
diff --git a/DEPS b/DEPS
index c69abe0..1ecde89 100644
--- a/DEPS
+++ b/DEPS
@@ -341,7 +341,7 @@
   },
 
   'third_party/dxc': {
-    'url': '{chromium_git}/external/github.com/microsoft/DirectXShaderCompiler@8b406b5717ca17874bd6b2ce832a8802c6fb3979',
+    'url': '{chromium_git}/external/github.com/microsoft/DirectXShaderCompiler@2a6bacd8712b040c5ab490c80dfa7553a355d2e0',
   },
 
   'third_party/dxheaders': {
diff --git a/third_party/dxc b/third_party/dxc
index 8b406b5..2a6bacd 160000
--- a/third_party/dxc
+++ b/third_party/dxc
@@ -1 +1 @@
-Subproject commit 8b406b5717ca17874bd6b2ce832a8802c6fb3979
+Subproject commit 2a6bacd8712b040c5ab490c80dfa7553a355d2e0