Re-land: base: Fix registering of memory pressure listeners used when emulating discardable memory.

base/memory/discardable_memory_provider_unittest.cc

 // Copyright 2013 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/memory/discardable_memory_provider.h"
 
 #include "base/bind.h"
 #include "base/memory/discardable_memory.h"
 #include "base/run_loop.h"
 #include "base/synchronization/waitable_event.h"
@@ skipping 46 matching lines @@
     internal::DiscardableMemoryProvider* provider_;
     scoped_ptr<uint8, FreeDeleter> memory_;
     bool is_locked_;
 
     DISALLOW_COPY_AND_ASSIGN(TestDiscardableMemory);
   };
 
   DiscardableMemoryProviderTestBase()
       : message_loop_(MessageLoop::TYPE_IO),
         provider_(new internal::DiscardableMemoryProvider) {
+    provider_->RegisterMemoryPressureListener();
   }
 
  protected:
   bool IsRegistered(const DiscardableMemory* discardable) {
     return provider_->IsRegisteredForTest(discardable);
   }
 
   bool CanBePurged(const DiscardableMemory* discardable) {
     return provider_->CanBePurgedForTest(discardable);
   }
@@ skipping 322 matching lines @@
       Bind(&ThreadedDiscardableMemoryProviderTest::UseMemoryHelper,
            Unretained(this)));
   memory_usage_thread_.message_loop()->PostTask(
       FROM_HERE,
       Bind(&ThreadedDiscardableMemoryProviderTest::SignalHelper,
            Unretained(this)));
   thread_sync_.Wait();
 }
 
 }  // namespace base