base: Add soft memory limit to DiscardableMemoryManager.

base/memory/discardable_memory_emulated.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_emulated.h"
 
 #include "base/lazy_instance.h"
 #include "base/memory/discardable_memory_manager.h"
 
 namespace base {
 namespace {
 
 // This is admittedly pretty magical. It's approximately enough memory for four
 // 2560x1600 images.
 const size_t kEmulatedMemoryLimit = 64 * 1024 * 1024;
 const size_t kEmulatedBytesToKeepUnderModeratePressure =
     kEmulatedMemoryLimit / 4;
 
 struct SharedState {
   SharedState()
       : manager(kEmulatedMemoryLimit,
-                kEmulatedBytesToKeepUnderModeratePressure) {}
+                kEmulatedMemoryLimit,
+                kEmulatedBytesToKeepUnderModeratePressure,
+                TimeDelta::Max()) {}
 
   internal::DiscardableMemoryManager manager;
 };
 LazyInstance<SharedState>::Leaky g_shared_state = LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
 namespace internal {
 
 DiscardableMemoryEmulated::DiscardableMemoryEmulated(size_t bytes)
@@ skipping 12 matching lines @@
 void DiscardableMemoryEmulated::RegisterMemoryPressureListeners() {
   g_shared_state.Pointer()->manager.RegisterMemoryPressureListener();
 }
 
 // static
 void DiscardableMemoryEmulated::UnregisterMemoryPressureListeners() {
   g_shared_state.Pointer()->manager.UnregisterMemoryPressureListener();
 }
 
 // static
+bool DiscardableMemoryEmulated::ReduceMemoryUsage() {
+  return g_shared_state.Pointer()->manager.ReduceMemoryUsage();
+}
+
+// static
 void DiscardableMemoryEmulated::PurgeForTesting() {
   g_shared_state.Pointer()->manager.PurgeAll();
 }
 
 bool DiscardableMemoryEmulated::Initialize() {
   return Lock() != DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
 }
 
 DiscardableMemoryLockStatus DiscardableMemoryEmulated::Lock() {
   DCHECK(!is_locked_);
@@ skipping 26 matching lines @@
   memory_.reset(new uint8[bytes_]);
   return false;
 }
 
 void DiscardableMemoryEmulated::Purge() {
   memory_.reset();
 }
 
 }  // namespace internal
 }  // namespace base