base: Remove non-caching discardable memory implementation.

base/memory/discardable_memory_mac.cc

Index: base/memory/discardable_memory_mac.cc
diff --git a/base/memory/discardable_memory_mac.cc b/base/memory/discardable_memory_mac.cc
index 65cae00992c253509bf988626e3640a5a2a0d693..01194ec8d785763aa0b61715a58f1b442d8e8a06 100644
--- a/base/memory/discardable_memory_mac.cc
+++ b/base/memory/discardable_memory_mac.cc
@@ -13,7 +13,6 @@
 #include "base/mac/mach_logging.h"
 #include "base/mac/scoped_mach_vm.h"
 #include "base/memory/discardable_memory_emulated.h"
-#include "base/memory/discardable_memory_malloc.h"
 #include "base/memory/discardable_memory_manager.h"
 #include "base/memory/scoped_ptr.h"
 
@@ -165,8 +164,7 @@ void DiscardableMemory::GetSupportedTypes(
     std::vector<DiscardableMemoryType>* types) {
   const DiscardableMemoryType supported_types[] = {
     DISCARDABLE_MEMORY_TYPE_MAC,
-    DISCARDABLE_MEMORY_TYPE_EMULATED,
-    DISCARDABLE_MEMORY_TYPE_MALLOC
+    DISCARDABLE_MEMORY_TYPE_EMULATED
   };
   types->assign(supported_types, supported_types + arraysize(supported_types));
 }
@@ -190,14 +188,6 @@ scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
 
       return memory.PassAs<DiscardableMemory>();
     }
-    case DISCARDABLE_MEMORY_TYPE_MALLOC: {
-      scoped_ptr<internal::DiscardableMemoryMalloc> memory(
-          new internal::DiscardableMemoryMalloc(size));
-      if (!memory->Initialize())
-        return scoped_ptr<DiscardableMemory>();
-
-      return memory.PassAs<DiscardableMemory>();
-    }
     case DISCARDABLE_MEMORY_TYPE_NONE:
     case DISCARDABLE_MEMORY_TYPE_ASHMEM:
       NOTREACHED();