gpu: Generate mailboxes on client side

gpu/command_buffer/common/mailbox.cc

Index: gpu/command_buffer/common/mailbox.cc
diff --git a/gpu/command_buffer/common/mailbox.cc b/gpu/command_buffer/common/mailbox.cc
index 8d8393fa63c0a647a992c98d6619156e01e75a92..0a3a942a09392b1e3ffdacd30486d741edb93e72 100644
--- a/gpu/command_buffer/common/mailbox.cc
+++ b/gpu/command_buffer/common/mailbox.cc
@@ -7,6 +7,7 @@
 #include <string.h>
 
 #include "base/logging.h"
+#include "crypto/random.h"
 
 namespace gpu {
 
@@ -31,4 +32,27 @@ void Mailbox::SetName(const int8* n) {
   memcpy(name, n, sizeof(name));
 }
 
+Mailbox Mailbox::Generate() {
+  Mailbox result;
+  crypto::RandBytes(result.name, sizeof(result.name));
+#if !defined(NDEBUG)
+  int8 value = 1;
+  for (size_t i = 1; i < sizeof(result.name); ++i)
+    value ^= result.name[i];
+  result.name[0] = value;
+#endif
+  return result;
+}
+
+bool Mailbox::Verify() const {
+#if !defined(NDEBUG)
+  int8 value = 1;
+  for (size_t i = 0; i < sizeof(name); ++i)
+    value ^= name[i];
+  return value == 0;
+#else
+  return true;
+#endif
+}
+
 }  // namespace gpu