Bump protobuf version

This is to pick up changes to remove deprecated use of `is_pod<>`.

The CMakeLists.txt file has moved to the root directory. Add some new
warning suppressions.

Change-Id: Id58fc9a8e9e467accd877c7b58f80331a2f5f0c6
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/148082
Auto-Submit: James Price <jrprice@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
diff --git a/DEPS b/DEPS
index 246e930..f3859fc 100644
--- a/DEPS
+++ b/DEPS
@@ -257,7 +257,7 @@
 
   # Misc dependencies inherited from Tint
   'third_party/protobuf': {
-    'url': '{chromium_git}/external/github.com/protocolbuffers/protobuf.git@fde7cf7358ec7cd69e8db9be4f1fa6a5c431386a',
+    'url': '{chromium_git}/external/github.com/protocolbuffers/protobuf.git@2b673bbb57e34fe1bd4570f726fc86b769a3a3d2',
     'condition': 'dawn_standalone',
   },
 }
diff --git a/src/tint/fuzzers/tint_ast_fuzzer/CMakeLists.txt b/src/tint/fuzzers/tint_ast_fuzzer/CMakeLists.txt
index 8d22901..1cb440a 100644
--- a/src/tint/fuzzers/tint_ast_fuzzer/CMakeLists.txt
+++ b/src/tint/fuzzers/tint_ast_fuzzer/CMakeLists.txt
@@ -22,6 +22,12 @@
   endif()
   target_compile_definitions(${NAME} PRIVATE CUSTOM_MUTATOR)
   target_include_directories(${NAME} PRIVATE ${CMAKE_BINARY_DIR})
+  target_compile_options(${NAME} PRIVATE
+        -Wno-conditional-uninitialized
+        -Wno-covered-switch-default
+        -Wno-shadow-field-in-constructor
+        -Wno-shorten-64-to-32
+        -Wno-undef)
 endfunction()
 
 set(PROTOBUF_SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/protobufs/tint_ast_fuzzer.proto)
@@ -93,6 +99,12 @@
 target_link_libraries(libtint_ast_fuzzer protobuf::libprotobuf libtint)
 tint_default_compile_options(libtint_ast_fuzzer)
 target_include_directories(libtint_ast_fuzzer PRIVATE ${CMAKE_BINARY_DIR})
+target_compile_options(libtint_ast_fuzzer PRIVATE
+        -Wno-conditional-uninitialized
+        -Wno-covered-switch-default
+        -Wno-shadow-field-in-constructor
+        -Wno-shorten-64-to-32
+        -Wno-undef)
 
 set(AST_FUZZER_SOURCES
         cli.cc
@@ -135,7 +147,11 @@
     target_compile_options(tint_ast_fuzzer_unittests PRIVATE
             -Wno-global-constructors
             -Wno-weak-vtables
-            -Wno-covered-switch-default)
+            -Wno-conditional-uninitialized
+            -Wno-covered-switch-default
+            -Wno-shadow-field-in-constructor
+            -Wno-shorten-64-to-32
+            -Wno-undef)
 
     target_include_directories(tint_ast_fuzzer_unittests PRIVATE ${CMAKE_BINARY_DIR})
 
diff --git a/src/tint/fuzzers/tint_spirv_tools_fuzzer/CMakeLists.txt b/src/tint/fuzzers/tint_spirv_tools_fuzzer/CMakeLists.txt
index 28bb473..0e2f98f 100644
--- a/src/tint/fuzzers/tint_spirv_tools_fuzzer/CMakeLists.txt
+++ b/src/tint/fuzzers/tint_spirv_tools_fuzzer/CMakeLists.txt
@@ -54,6 +54,8 @@
     )
     tint_default_compile_options(${NAME})
     target_compile_options(${NAME} PRIVATE
+        -Wno-conditional-uninitialized
+        -Wno-covered-switch-default
         -Wno-missing-prototypes
         -Wno-zero-as-null-pointer-constant
         -Wno-reserved-id-macro
diff --git a/third_party/CMakeLists.txt b/third_party/CMakeLists.txt
index b1f269b..2081882 100644
--- a/third_party/CMakeLists.txt
+++ b/third_party/CMakeLists.txt
@@ -49,7 +49,7 @@
         (NOT TARGET protobuf::libprotobuf OR NOT TARGET protobuf::protoc))
     set(protobuf_BUILD_TESTS OFF CACHE BOOL "Controls whether protobuf tests are built" FORCE)
     set(protobuf_MSVC_STATIC_RUNTIME OFF CACHE BOOL "Controls whether a protobuf static runtime is built" FORCE)
-    add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/protobuf/cmake)
+    add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/protobuf)
 endif()
 
 if (NOT TARGET SPIRV-Tools)
diff --git a/third_party/protobuf b/third_party/protobuf
index fde7cf7..2b673bb 160000
--- a/third_party/protobuf
+++ b/third_party/protobuf
@@ -1 +1 @@
-Subproject commit fde7cf7358ec7cd69e8db9be4f1fa6a5c431386a
+Subproject commit 2b673bbb57e34fe1bd4570f726fc86b769a3a3d2