base: Use DiscardableMemoryManager on MacOSX.

This limits the address space used for discardable memory on MacOSX
by using the DiscardableMemoryManager for userspace eviction.

Includes some minor refactoring to keep all code using
DiscardableMemoryManager consistent.

BUG=369246

Review URL: https://codereview.chromium.org/261993003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269640 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 5 insertions, 11 deletions

diff --git a/base/memory/discardable_memory_manager.cc b/base/memory/discardable_memory_manager.cc
index 468690b..3e90d22 100644
--- a/base/memory/discardable_memory_manager.cc
+++ b/base/memory/discardable_memory_manager.cc
@@ -12,21 +12,15 @@
 
 namespace base {
 namespace internal {
-namespace {
 
-// This is admittedly pretty magical. It's approximately enough memory for eight
-// 2560x1600 images.
-static const size_t kDefaultMemoryLimit = 128 * 1024 * 1024;
-static const size_t kDefaultBytesToKeepUnderModeratePressure = 12 * 1024 * 1024;
-
-}  // namespace
-
-DiscardableMemoryManager::DiscardableMemoryManager()
+DiscardableMemoryManager::DiscardableMemoryManager(
+    size_t memory_limit,
+    size_t bytes_to_keep_under_moderate_pressure)
     : allocations_(AllocationMap::NO_AUTO_EVICT),
       bytes_allocated_(0),
-      memory_limit_(kDefaultMemoryLimit),
+      memory_limit_(memory_limit),
       bytes_to_keep_under_moderate_pressure_(
-          kDefaultBytesToKeepUnderModeratePressure) {
+          bytes_to_keep_under_moderate_pressure) {
   BytesAllocatedChanged();
 }