Set DISCARDABLE_MEMORY_ALWAYS_SUPPORTED_NATIVELY to true on Android.

content/renderer/render_process_visibility_manager.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 "content/renderer/render_process_visibility_manager.h"
 
 #include "base/logging.h"
 #include "base/memory/memory_pressure_listener.h"
 
 namespace content {
 
 RenderProcessVisibilityManager::RenderProcessVisibilityManager()
     : num_visible_render_widgets_(0) {
 }
 
 RenderProcessVisibilityManager::~RenderProcessVisibilityManager() {
 }
 
 // static
 RenderProcessVisibilityManager* RenderProcessVisibilityManager::GetInstance() {
   return Singleton<RenderProcessVisibilityManager>::get();
 }
 
 void RenderProcessVisibilityManager::WidgetVisibilityChanged(bool visible) {
-#if !defined(DISCARDABLE_MEMORY_ALWAYS_SUPPORTED_NATIVELY)
+#if !defined(SYSTEM_NATIVELY_SIGNALS_MEMORY_PRESSURE)
   num_visible_render_widgets_ += visible ? 1 : -1;
   DCHECK_LE(0, num_visible_render_widgets_);
   if (num_visible_render_widgets_ == 0) {
     // TODO(vollick): Remove this this heavy-handed approach once we're polling
     // the real system memory pressure.
     base::MemoryPressureListener::NotifyMemoryPressure(
-        base::MemoryPressureListener::MEMORY_PRESSURE_CRITICAL);
+        base::MemoryPressureListener::MEMORY_PRESSURE_MODERATE);
   }
 #endif
 }
 
 }  // namespace content