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

content/renderer/render_thread_impl.cc

 // Copyright (c) 2012 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 "content/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <vector>
@@ skipping 412 matching lines @@
                   supported_types.end(),
                   requested_type) != supported_types.end()) {
       type = requested_type;
     } else {
       LOG(ERROR) << "Requested discardable memory type is not supported.";
     }
   }
 
   base::DiscardableMemory::SetPreferredType(type);
 
+  // Allow discardable memory implementations to register memory pressure
+  // listeners.
+  base::DiscardableMemory::RegisterMemoryPressureListeners();
+
   // AllocateGpuMemoryBuffer must be used exclusively on one thread but
   // it doesn't have to be the same thread RenderThreadImpl is created on.
   allocate_gpu_memory_buffer_thread_checker_.DetachFromThread();
 
   TRACE_EVENT_END_ETW("RenderThreadImpl::Init", 0, "");
 }
 
 RenderThreadImpl::~RenderThreadImpl() {
 }
 
@@ skipping 953 matching lines @@
   hidden_widget_count_--;
 
   if (!GetContentClient()->renderer()->RunIdleHandlerWhenWidgetsHidden()) {
     return;
   }
 
   ScheduleIdleHandler(kLongIdleHandlerDelayMs);
 }
 
 }  // namespace content