[tracing] Expose AddOwnershipEdge and CreateAllocatorDump with guid to blink. (blink-side).

public/platform/WebMemoryAllocatorDump.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 WebMemoryAllocatorDump_h
 #define WebMemoryAllocatorDump_h
 
 #include "WebCommon.h"
 #include "WebString.h"
 
 namespace blink {
 
+// Class which has the guid of the WebMemoryAllocatorDump. The guid can either
+// be uint64_t or WebString.
+struct BLINK_PLATFORM_EXPORT WebMemoryAllocatorDumpGuid {
+    enum GuidType {
+        Int64Type,

[Primiano Tucci (use gerrit), 2015/05/29 11:24:53]

Technically this is a uint64 not int64, so either you call this Uint64Type or
just IntType (I'd prefer the latter)

[ssid, 2015/05/29 15:50:48]

Done.

+        StringType
+    };
+
+    const uint64_t guidInt64;
+    const WebString guidString;
+    const GuidType type;
+
+    explicit WebMemoryAllocatorDumpGuid(const uint64_t guid)
+        : guidInt64(guid)
+        , guidString()
+        , type(Int64Type)
+    {
+    }
+
+    explicit WebMemoryAllocatorDumpGuid(const WebString& guid)
+        : guidInt64(0)
+        , guidString(guid)
+        , type(StringType)
+    {
+    }
+};
+
 // A container which holds all the attributes of a particular dump for a given
 // allocator.
 class BLINK_PLATFORM_EXPORT WebMemoryAllocatorDump {
 public:
     virtual ~WebMemoryAllocatorDump();
 
     // Adds a scalar attribute to the dump.
     // Arguments:
     //   name: name of the attribute. Typical names, emitted by most allocators
     //       dump providers are: "outer_size", "inner_size", "objects_count".
     //   units: the units for the attribute. Gives a hint to the trace-viewer UI
     //       about the semantics of the attribute.
     //       Currently supported values are "bytes" and "objects".
     //   value: the value of the attribute.
     virtual void AddScalar(const WebString& name, const char* units, uint64_t value) { }
     virtual void AddString(const WebString& name, const char* units, const WebString& value) { }
 };
 
 } // namespace blink
 
 #endif // WebMemoryAllocatorDump_h