gpu: Add sync token dependencies to flush metadata.

gpu/command_buffer/common/sync_token.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef GPU_COMMAND_BUFFER_COMMON_SYNC_TOKEN_H_
 #define GPU_COMMAND_BUFFER_COMMON_SYNC_TOKEN_H_
 
 #include <stdint.h>
 #include <string.h>
 
+#include <tuple>
+
 #include "gpu/command_buffer/common/command_buffer_id.h"
 #include "gpu/command_buffer/common/constants.h"
 #include "gpu/gpu_export.h"
 
 // From glextchromium.h.
 #ifndef GL_SYNC_TOKEN_SIZE_CHROMIUM
 #define GL_SYNC_TOKEN_SIZE_CHROMIUM 24
 #endif
 
 namespace gpu {
@@ skipping 49 matching lines @@
   CommandBufferId command_buffer_id() const { return command_buffer_id_; }
   uint64_t release_count() const { return release_count_; }
 
   // This extra data field can be used by command buffers to add extra
   // information to identify unverified sync tokens. The current purpose
   // of this field is only for unverified sync tokens which only exist within
   // the same process so this information will not survive cross-process IPCs.
   int32_t extra_data_field() const { return extra_data_field_; }
 
   bool operator<(const SyncToken& other) const {
-    // TODO(dyen): Once all our compilers support c++11, we can replace this
-    // long list of comparisons with std::tie().
-    return (namespace_id_ < other.namespace_id()) ||
-           ((namespace_id_ == other.namespace_id()) &&
-            ((command_buffer_id_ < other.command_buffer_id()) ||
-             ((command_buffer_id_ == other.command_buffer_id()) &&
-              (release_count_ < other.release_count()))));
+    return std::tie(namespace_id_, command_buffer_id_, release_count_) <
+           std::tie(other.namespace_id_, other.command_buffer_id_,
+                    other.release_count_);
   }
 
   bool operator==(const SyncToken& other) const {
     return verified_flush_ == other.verified_flush() &&
            namespace_id_ == other.namespace_id() &&
            extra_data_field_ == other.extra_data_field() &&
            command_buffer_id_ == other.command_buffer_id() &&
            release_count_ == other.release_count();
   }
 
   bool operator!=(const SyncToken& other) const { return !(*this == other); }
 
  private:
   bool verified_flush_;
   CommandBufferNamespace namespace_id_;
   int32_t extra_data_field_;
   CommandBufferId command_buffer_id_;
   uint64_t release_count_;
 };
 
 static_assert(sizeof(SyncToken) <= GL_SYNC_TOKEN_SIZE_CHROMIUM,
               "SyncToken size must not exceed GL_SYNC_TOKEN_SIZE_CHROMIUM");
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_SYNC_TOKEN_H_