base: Add soft memory limit to DiscardableMemoryManager.

base/memory/discardable_memory_android.cc

Index: base/memory/discardable_memory_android.cc
diff --git a/base/memory/discardable_memory_android.cc b/base/memory/discardable_memory_android.cc
index c3de3a36b3d9bac3fa8d035dd7eb8fad7891c400..c929a8768434ea973520244182db1535342aa689 100644
--- a/base/memory/discardable_memory_android.cc
+++ b/base/memory/discardable_memory_android.cc
@@ -32,7 +32,10 @@ size_t GetOptimalAshmemRegionSizeForAllocator() {
 // Holds the shared state used for allocations.
 struct SharedState {
   SharedState()
-      : manager(kAshmemMemoryLimit, kAshmemMemoryLimit),
+      : manager(kAshmemMemoryLimit,
+                kAshmemMemoryLimit,
+                kAshmemMemoryLimit,
+                TimeDelta::Max()),
         allocator(kAshmemAllocatorName,
                   GetOptimalAshmemRegionSizeForAllocator()) {}
 
@@ -54,6 +57,11 @@ void DiscardableMemory::UnregisterMemoryPressureListeners() {
 }
 
 // static
+bool DiscardableMemory::IdleNotification() {
+  return internal::DiscardableMemoryEmulated::IdleNotification();
+}
+
+// static
 void DiscardableMemory::GetSupportedTypes(
     std::vector<DiscardableMemoryType>* types) {
   const DiscardableMemoryType supported_types[] = {