[Compiler Fix] Backport - Bring declarations and definitions to be in…

… sync (#32911) (#32915)

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src/core/ext/gcp/metadata_query.cc

@@ -46,16 +46,11 @@ namespace grpc_core {
 
 TraceFlag grpc_metadata_query_trace(false, "metadata_query");
 
-constexpr const char MetadataQuery::kZoneAttribute[] =
-    "/computeMetadata/v1/instance/zone";
-constexpr const char MetadataQuery::kClusterNameAttribute[] =
-    "/computeMetadata/v1/instance/attributes/cluster-name";
-constexpr const char MetadataQuery::kRegionAttribute[] =
-    "/computeMetadata/v1/instance/region";
-constexpr const char MetadataQuery::kInstanceIdAttribute[] =
-    "/computeMetadata/v1/instance/id";
-constexpr const char MetadataQuery::kIPv6Attribute[] =
-    "/computeMetadata/v1/instance/network-interfaces/0/ipv6s";
+constexpr const char MetadataQuery::kZoneAttribute[];
+constexpr const char MetadataQuery::kClusterNameAttribute[];
+constexpr const char MetadataQuery::kRegionAttribute[];
+constexpr const char MetadataQuery::kInstanceIdAttribute[];
+constexpr const char MetadataQuery::kIPv6Attribute[];
 
 MetadataQuery::MetadataQuery(
     std::string attribute, grpc_polling_entity* pollent,

src/core/ext/gcp/metadata_query.h

@@ -38,11 +38,16 @@ namespace grpc_core {
 // environment.
 class MetadataQuery : public InternallyRefCounted<MetadataQuery> {
  public:
-  static const char kZoneAttribute[];
-  static const char kClusterNameAttribute[];
-  static const char kRegionAttribute[];
-  static const char kInstanceIdAttribute[];
-  static const char kIPv6Attribute[];
+  static constexpr const char kZoneAttribute[] =
+      "/computeMetadata/v1/instance/zone";
+  static constexpr const char kClusterNameAttribute[] =
+      "/computeMetadata/v1/instance/attributes/cluster-name";
+  static constexpr const char kRegionAttribute[] =
+      "/computeMetadata/v1/instance/region";
+  static constexpr const char kInstanceIdAttribute[] =
+      "/computeMetadata/v1/instance/id";
+  static constexpr const char kIPv6Attribute[] =
+      "/computeMetadata/v1/instance/network-interfaces/0/ipv6s";
 
   MetadataQuery(
       std::string attribute, grpc_polling_entity* pollent,

src/core/lib/event_engine/event_engine.cc

@@ -20,10 +20,10 @@
 namespace grpc_event_engine {
 namespace experimental {
 
-constexpr EventEngine::TaskHandle EventEngine::TaskHandle::kInvalid = {-1, -1};
-constexpr EventEngine::ConnectionHandle
-    EventEngine::ConnectionHandle::kInvalid = {-1, -1};
-constexpr EventEngine::DNSResolver::LookupTaskHandle
+const EventEngine::TaskHandle EventEngine::TaskHandle::kInvalid = {-1, -1};
+const EventEngine::ConnectionHandle EventEngine::ConnectionHandle::kInvalid = {
+    -1, -1};
+const EventEngine::DNSResolver::LookupTaskHandle
     EventEngine::DNSResolver::LookupTaskHandle::kInvalid = {-1, -1};
 
 bool operator==(const EventEngine::TaskHandle& lhs,