Update from https://crrev.com/316786

base/memory/discardable_memory_linux.cc

Index: base/memory/discardable_memory_linux.cc
diff --git a/base/memory/discardable_memory_linux.cc b/base/memory/discardable_memory_linux.cc
index 9b4e9401ce4ff7c006756a9a5ed6a245431662c9..977b029bee59c4a9155dc524a88274bc1d7319c4 100644
--- a/base/memory/discardable_memory_linux.cc
+++ b/base/memory/discardable_memory_linux.cc
@@ -11,11 +11,6 @@
 namespace base {
 
 // static
-void DiscardableMemory::ReleaseFreeMemory() {
-  internal::DiscardableMemoryShmem::ReleaseFreeMemory();
-}
-
-// static
 bool DiscardableMemory::ReduceMemoryUsage() {
   return internal::DiscardableMemoryEmulated::ReduceMemoryUsage();
 }
@@ -61,10 +56,4 @@ scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
   return nullptr;
 }
 
-// static
-void DiscardableMemory::PurgeForTesting() {
-  internal::DiscardableMemoryEmulated::PurgeForTesting();
-  internal::DiscardableMemoryShmem::PurgeForTesting();
-}
-
 }  // namespace base