Introducing gpu::CommandBufferId as a distinct, IdType<...>-based type.

gpu/ipc/gpu_command_buffer_traits.cc

Index: gpu/ipc/gpu_command_buffer_traits.cc
diff --git a/gpu/ipc/gpu_command_buffer_traits.cc b/gpu/ipc/gpu_command_buffer_traits.cc
index eecc1374b215d2bdd483c42e0fb41cfb7b2f81d6..450e8ae8c36531a1fbbb45620a6b2d3b0ad56bbd 100644
--- a/gpu/ipc/gpu_command_buffer_traits.cc
+++ b/gpu/ipc/gpu_command_buffer_traits.cc
@@ -7,6 +7,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "gpu/command_buffer/common/command_buffer_id.h"
 #include "gpu/command_buffer/common/mailbox_holder.h"
 #include "gpu/command_buffer/common/sync_token.h"
 #include "gpu/command_buffer/common/value_state.h"
@@ -72,7 +73,7 @@ bool ParamTraits<gpu::SyncToken>::Read(const base::Pickle* m,
   bool verified_flush = false;
   gpu::CommandBufferNamespace namespace_id =
       gpu::CommandBufferNamespace::INVALID;
-  uint64_t command_buffer_id = 0;
+  gpu::CommandBufferId command_buffer_id;
   uint64_t release_count = 0;
 
   if (!ReadParam(m, iter, &verified_flush) ||
@@ -93,10 +94,10 @@ bool ParamTraits<gpu::SyncToken>::Read(const base::Pickle* m,
 }
 
 void ParamTraits<gpu::SyncToken>::Log(const param_type& p, std::string* l) {
-  *l +=
-      base::StringPrintf("[%d:%llX] %llu", static_cast<int>(p.namespace_id()),
-                         static_cast<unsigned long long>(p.command_buffer_id()),
-                         static_cast<unsigned long long>(p.release_count()));
+  *l += base::StringPrintf(
+      "[%d:%llX] %llu", static_cast<int>(p.namespace_id()),
+      static_cast<unsigned long long>(p.command_buffer_id().GetUnsafeValue()),
+      static_cast<unsigned long long>(p.release_count()));
 }
 
 void ParamTraits<gpu::Mailbox>::Write(base::Pickle* m, const param_type& p) {