Revert "base: Implement browser process support for discardable memory."

ash/test/test_suite.cc

Index: ash/test/test_suite.cc
diff --git a/ash/test/test_suite.cc b/ash/test/test_suite.cc
index 80d61f4fb4429f51cc7aa7ae5e65ca5ba1cfa7ef..1b7eb4658f34480e41bb47888695f3ab29ab920f 100644
--- a/ash/test/test_suite.cc
+++ b/ash/test/test_suite.cc
@@ -52,9 +52,6 @@ void AuraShellTestSuite::Initialize() {
   // output, it'll pass regardless of the system language.
   ui::ResourceBundle::InitSharedInstanceWithLocale(
       "en-US", NULL, ui::ResourceBundle::LOAD_COMMON_RESOURCES);
-
-  base::DiscardableMemoryShmemAllocator::SetInstance(
-      &discardable_memory_allocator_);
 }
 
 void AuraShellTestSuite::Shutdown() {