Update from https://crrev.com/316786

base/memory/discardable_memory_emulated.cc

Index: base/memory/discardable_memory_emulated.cc
diff --git a/base/memory/discardable_memory_emulated.cc b/base/memory/discardable_memory_emulated.cc
index 43034006319f181888a2c3dde2068f0518981ab7..b12d7ce0eadbc5648a2a5e1aab0484a3dce6577f 100644
--- a/base/memory/discardable_memory_emulated.cc
+++ b/base/memory/discardable_memory_emulated.cc
@@ -68,11 +68,6 @@ void DiscardableMemoryEmulated::ReduceMemoryUsageUntilWithinLimit(
   g_manager.Pointer()->ReduceMemoryUsageUntilWithinLimit(bytes);
 }
 
-// static
-void DiscardableMemoryEmulated::PurgeForTesting() {
-  g_manager.Pointer()->PurgeAll();
-}
-
 bool DiscardableMemoryEmulated::Initialize() {
   return Lock() != DISCARDABLE_MEMORY_LOCK_STATUS_FAILED;
 }
@@ -113,9 +108,5 @@ void DiscardableMemoryEmulated::Purge() {
   memory_.reset();
 }
 
-bool DiscardableMemoryEmulated::IsMemoryResident() const {
-  return true;
-}
-
 }  // namespace internal
 }  // namespace base