Use DiscardableMemoryManager on Android.

base/memory/discardable_memory_android.cc

Index: base/memory/discardable_memory_android.cc
diff --git a/base/memory/discardable_memory_android.cc b/base/memory/discardable_memory_android.cc
index fa89c189db7be5170ecf30ea3a2a882c24fc87db..2412737fed4232722e7215ba940c9a5d008db22d 100644
--- a/base/memory/discardable_memory_android.cc
+++ b/base/memory/discardable_memory_android.cc
@@ -9,33 +9,46 @@
 #include "base/compiler_specific.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
-#include "base/memory/discardable_memory_allocator_android.h"
+#include "base/memory/discardable_memory_allocation_ashmem_factory.h"
+#include "base/memory/discardable_memory_ashmem.h"
 #include "base/memory/discardable_memory_emulated.h"
 #include "base/memory/discardable_memory_malloc.h"
+#include "base/memory/discardable_memory_manager.h"
 
 namespace base {
 namespace {
 
 const char kAshmemAllocatorName[] = "DiscardableMemoryAllocator";
 
-struct DiscardableMemoryAllocatorWrapper {
-  DiscardableMemoryAllocatorWrapper()
-      : allocator(kAshmemAllocatorName,
-                  GetOptimalAshmemRegionSizeForAllocator()) {
+// High limit used only to avoid running out of address space. The kernel takes
+// care of ensuring that we don't run out of physical memory.
+const size_t kDefaultDiscardableMemoryLimit = 512 * 1024 * 1024;
+
+class DiscardableMemoryManagerImpl {

[reveman, 2014/03/20 19:33:44]

This is not a DiscardableMemoryManagerImpl. This should be consistent with
whatever we're doing in discardable_memory_emulated.cc. Currently that means
DiscardableMemoryManagerImpl implementing both the manager and factory
interfaces. If you don't like that for some reason, we need to first adjust how
we do things in discardable_memory_emulated.cc. Consistency is more important to
me than what specific pattern we use.

[Philippe, 2014/03/21 10:17:44]

Agreed for consistency. Let's discuss this in your CL. Subclassing the ashmem
factory is not suitable/desirable here.

+ public:
+  DiscardableMemoryManagerImpl()
+      : factory_(
+          kAshmemAllocatorName, GetOptimalAshmemRegionSizeForAllocator()),
+        manager_(&factory_, kDefaultDiscardableMemoryLimit) {
   }
 
-  internal::DiscardableMemoryAllocator allocator;
+  internal::DiscardableMemoryManager* instance() {
+    return &manager_;
+  }
 
  private:
   // Returns 64 MBytes for a 512 MBytes device, 128 MBytes for 1024 MBytes...
   static size_t GetOptimalAshmemRegionSizeForAllocator() {
     // Note that this may do some I/O (without hitting the disk though) so it
     // should not be called on the critical path.
-    return base::android::SysUtils::AmountOfPhysicalMemoryKB() * 1024 / 8;
+    return android::SysUtils::AmountOfPhysicalMemoryKB() * 1024 / 8;
   }
+
+  internal::DiscardableMemoryAllocationAshmemFactory factory_;
+  internal::DiscardableMemoryManager manager_;
 };
 
-LazyInstance<DiscardableMemoryAllocatorWrapper>::Leaky g_context =
+LazyInstance<DiscardableMemoryManagerImpl>::Leaky g_manager =
     LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
@@ -69,7 +82,13 @@ scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemoryWithType(
     case DISCARDABLE_MEMORY_TYPE_MAC:
       return scoped_ptr<DiscardableMemory>();
     case DISCARDABLE_MEMORY_TYPE_ANDROID: {
-      return g_context.Pointer()->allocator.Allocate(size);
+      scoped_ptr<internal::DiscardableMemoryAshmem> memory(
+          new internal::DiscardableMemoryAshmem(
+              g_manager.Get().instance(), size));
+      if (!memory->Initialize())
+        return scoped_ptr<DiscardableMemory>();
+
+      return memory.PassAs<DiscardableMemory>();
     }
     case DISCARDABLE_MEMORY_TYPE_EMULATED: {
       scoped_ptr<internal::DiscardableMemoryEmulated> memory(