Make RenderPass::Id an isolated class

cc/quads/render_pass_id.h

+// Copyright 2014 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 CC_QUADS_RENDER_PASS_ID_H_
+#define CC_QUADS_RENDER_PASS_ID_H_
+
+#include "base/basictypes.h"
+#include "base/containers/hash_tables.h"
+#include "cc/base/cc_export.h"
+
+namespace cc {
+
+class CC_EXPORT RenderPassId {
+ public:
+  int layer_id;
+  int index;
+
+  RenderPassId(int layer_id, int index) : layer_id(layer_id), index(index) {}
+  void* AsTracingId() const;
+
+  bool operator==(const RenderPassId& other) const {
+    return layer_id == other.layer_id && index == other.index;
+  }
+  bool operator!=(const RenderPassId& other) const { return !(*this == other); }
+  bool operator<(const RenderPassId& other) const {
+    return layer_id < other.layer_id ||
+           (layer_id == other.layer_id && index < other.index);
+  }
+};
+
+}  // namespace cc
+
+#endif  // CC_QUADS_RENDER_PASS_ID_H_