base: Use DiscardableMemoryManager on MacOSX.

base/memory/discardable_memory_manager_unittest.cc

Index: base/memory/discardable_memory_manager_unittest.cc
diff --git a/base/memory/discardable_memory_manager_unittest.cc b/base/memory/discardable_memory_manager_unittest.cc
index c59d82e51695ef8531626faa8d1934cad74a62f0..408fc77029778b31e1782d1628a4e94e1de44678 100644
--- a/base/memory/discardable_memory_manager_unittest.cc
+++ b/base/memory/discardable_memory_manager_unittest.cc
@@ -44,7 +44,8 @@ class TestAllocationImpl : public internal::DiscardableMemoryManagerAllocation {
 
 class DiscardableMemoryManagerTestBase {
  public:
-  DiscardableMemoryManagerTestBase() {
+  DiscardableMemoryManagerTestBase()
+      : manager_(64 * 1024 * 1024, 12 * 1024 * 1024) {

[willchan no longer on Chromium, 2014/05/05 22:39:28]

Can you add a comment here for why you chose these values? Is it safe to change?
I suspect that the constants chosen in the tests are tightly coupled to these
constants. If that's true, please note that.

[reveman, 2014/05/06 14:26:46]

Reduced the size of these constants and added a comment to latest patch.

     manager_.RegisterMemoryPressureListener();
   }