Fix end_to_end_shared_memory_fuzzer.

Before 8a689afd048a60cc76e7543d9d8c4193df351f96 this was a no-op because
we forgot to set the TracePacket size. After that we would crash because
most data would fail to parse as a packet.

Change-Id: I37a95f0062fc87d2bdaa78eaac1284c662d88f37
diff --git a/test/end_to_end_shared_memory_fuzzer.cc b/test/end_to_end_shared_memory_fuzzer.cc
index 782cc30..91f3629 100644
--- a/test/end_to_end_shared_memory_fuzzer.cc
+++ b/test/end_to_end_shared_memory_fuzzer.cc
@@ -140,12 +140,20 @@
   std::function<void()> on_produced_and_committed_;
 };
 
+class FuzzTestHelper : public TestHelper {
+ public:
+  explicit FuzzTestHelper(base::TestTaskRunner* task_runner)
+      : TestHelper(task_runner) {}
+  // Do not verify the data, as it will most likely be corrupted.
+  void ReadTraceData(std::vector<TracePacket>) override {}
+};
+
 int FuzzSharedMemory(const uint8_t* data, size_t size);
 
 int FuzzSharedMemory(const uint8_t* data, size_t size) {
   base::TestTaskRunner task_runner;
 
-  TestHelper helper(&task_runner);
+  FuzzTestHelper helper(&task_runner);
   helper.StartServiceIfRequired();
 
   auto cp =