[tracing] Fix MemoryDumpManager to support startup tracing

content/browser/tracing/memory_tracing_browsertest.cc

 // 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.
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/run_loop.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/memory_dump_provider.h"
@@ skipping 50 matching lines @@
     last_callback_dump_guid_ = dump_guid;
     last_callback_success_ = success;
     closure.Run();
   }
 
  protected:
   void SetUp() override {
     callback_call_count_ = 0;
     last_callback_dump_guid_ = 0;
     last_callback_success_ = false;
-    MemoryDumpManager::GetInstance()->Initialize();
+
+    // TODO(primiano): This should be done via TraceConfig.
+    // See https://goo.gl/5Hj3o0.
+    MemoryDumpManager::GetInstance()->DisablePeriodicDumpsForTesting();
+
     mock_dump_provider_.reset(new MockDumpProvider());
     MemoryDumpManager::GetInstance()->RegisterDumpProvider(
         mock_dump_provider_.get());
-    // TODO(primiano): This should be done via TraceConfig.
-    // See https://goo.gl/5Hj3o0.
-    MemoryDumpManager::GetInstance()->DisablePeriodicDumpsForTesting();
     ContentBrowserTest::SetUp();
   }
 
   void TearDown() override {
     MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
         mock_dump_provider_.get());
     mock_dump_provider_.reset();
     ContentBrowserTest::TearDown();
   }
 
@@ skipping 124 matching lines @@
 
   EnableMemoryTracing();
   RequestGlobalDumpAndWait(false /* from_renderer_thread */);
   EXPECT_EQ(1u, callback_call_count_);
   EXPECT_NE(0u, last_callback_dump_guid_);
   EXPECT_TRUE(last_callback_success_);
   DisableTracing();
 }
 
 }  // namespace content