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

ui/message_center/test/run_all_unittests.cc

Index: ui/message_center/test/run_all_unittests.cc
diff --git a/ui/message_center/test/run_all_unittests.cc b/ui/message_center/test/run_all_unittests.cc
index b0cc026cc1b160deaae29bbbbb85a03cb806e302..fa53d67492a44182ab62da53b46362ab1a98aca6 100644
--- a/ui/message_center/test/run_all_unittests.cc
+++ b/ui/message_center/test/run_all_unittests.cc
@@ -7,7 +7,6 @@
 #include "base/compiler_specific.h"
 #include "base/path_service.h"
 #include "base/test/launcher/unit_test_launcher.h"
-#include "base/test/test_discardable_memory_shmem_allocator.h"
 #include "base/test/test_suite.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/base/resource/resource_bundle.h"
@@ -38,9 +37,6 @@ class MessageCenterTestSuite : public base::TestSuite {
     base::FilePath ui_test_pak_path;
     ASSERT_TRUE(PathService::Get(ui::UI_TEST_PAK, &ui_test_pak_path));
     ui::ResourceBundle::InitSharedInstanceWithPakPath(ui_test_pak_path);
-
-    base::DiscardableMemoryShmemAllocator::SetInstance(
-        &discardable_memory_allocator_);
   }
 
   void Shutdown() override {
@@ -49,8 +45,6 @@ class MessageCenterTestSuite : public base::TestSuite {
   }
 
  private:
-  base::TestDiscardableMemoryShmemAllocator discardable_memory_allocator_;
-
   DISALLOW_COPY_AND_ASSIGN(MessageCenterTestSuite);
 };