Implement tracing interface for v8

test/cctest/heap/test-incremental-marking.cc

Index: test/cctest/heap/test-incremental-marking.cc
diff --git a/test/cctest/heap/test-incremental-marking.cc b/test/cctest/heap/test-incremental-marking.cc
index 1f63db5f46444d69925c07645493a5038ab0f125..5822d4a9792d33c3598be8eca65402f477510b1d 100644
--- a/test/cctest/heap/test-incremental-marking.cc
+++ b/test/cctest/heap/test-incremental-marking.cc
@@ -85,6 +85,28 @@ class MockPlatform : public v8::Platform {
     delete task;
   }
 
+  uint64_t AddTraceEvent(char phase, const uint8_t* categoryEnabledFlag,
+                         const char* name, uint64_t id, uint64_t bind_id,
+                         int numArgs, const char** argNames,
+                         const uint8_t* argTypes, const uint64_t* argValues,
+                         unsigned int flags) override {
+    return 0;
+  }
+
+  void UpdateTraceEventDuration(const uint8_t* categoryEnabledFlag,
+                                const char* name, uint64_t handle) override {}
+
+  const uint8_t* GetCategoryGroupEnabled(const char* name) override {
+    static uint8_t no = 0;
+    return &no;
+  }
+
+  const char* GetCategoryGroupName(
+      const uint8_t* categoryEnabledFlag) override {
+    static const char* dummy = "dummy";
+    return dummy;
+  }
+
  private:
   v8::Platform* platform_;
   IdleTask* idle_task_;