base: Rename discardable memory allocator interface and remove unnecessary class.

There's only one discardable memory allocator interface. Rename it
to DiscardableMemoryAllocator. DiscardableMemoryShmemChunk class
is unnecessary, remove it.

BUG=442945,422953

Review URL: https://codereview.chromium.org/1001873002

Cr-Commit-Position: refs/heads/master@{#321008}

29 files changed, 230 insertions, 322 deletions

diff --git a/ash/test/test_suite.cc b/ash/test/test_suite.cc
index 80d61f4..4f1ead0 100644
--- a/ash/test/test_suite.cc
+++ b/ash/test/test_suite.cc
@@ -53,8 +53,7 @@ void AuraShellTestSuite::Initialize() {
   ui::ResourceBundle::InitSharedInstanceWithLocale(
       "en-US", NULL, ui::ResourceBundle::LOAD_COMMON_RESOURCES);
 
-  base::DiscardableMemoryShmemAllocator::SetInstance(
-      &discardable_memory_allocator_);
+  base::DiscardableMemoryAllocator::SetInstance(&discardable_memory_allocator_);
 }
 
 void AuraShellTestSuite::Shutdown() {
diff --git a/ash/test/test_suite.h b/ash/test/test_suite.h
index e2e0957..e740bac 100644
--- a/ash/test/test_suite.h
+++ b/ash/test/test_suite.h
@@ -6,7 +6,7 @@
 #define ASH_TEST_TEST_SUITE_H_
 
 #include "base/compiler_specific.h"
-#include "base/test/test_discardable_memory_shmem_allocator.h"
+#include "base/test/test_discardable_memory_allocator.h"
 #include "base/test/test_suite.h"
 
 #if defined(OS_WIN)
@@ -31,7 +31,7 @@ class AuraShellTestSuite : public base::TestSuite {
   scoped_ptr<base::win::ScopedCOMInitializer> com_initializer_;
 #endif
 
-  base::TestDiscardableMemoryShmemAllocator discardable_memory_allocator_;
+  base::TestDiscardableMemoryAllocator discardable_memory_allocator_;
 };
 
 }  // namespace test
diff --git a/base/base.gyp b/base/base.gyp
index c7a2481..80da0d1 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -975,8 +975,8 @@
         'test/simple_test_tick_clock.h',
         'test/task_runner_test_template.cc',
         'test/task_runner_test_template.h',
-        'test/test_discardable_memory_shmem_allocator.cc',
-        'test/test_discardable_memory_shmem_allocator.h',
+        'test/test_discardable_memory_allocator.cc',
+        'test/test_discardable_memory_allocator.h',
         'test/test_file_util.cc',
         'test/test_file_util.h',
         'test/test_file_util_android.cc',
diff --git a/base/base.gypi b/base/base.gypi
index 13cba85..05e5de4 100644
--- a/base/base.gypi
+++ b/base/base.gypi
@@ -318,10 +318,8 @@
           'memory/aligned_memory.h',
           'memory/discardable_memory.cc',
           'memory/discardable_memory.h',
-          'memory/discardable_memory_shmem.cc',
-          'memory/discardable_memory_shmem.h',
-          'memory/discardable_memory_shmem_allocator.cc',
-          'memory/discardable_memory_shmem_allocator.h',
+          'memory/discardable_memory_allocator.cc',
+          'memory/discardable_memory_allocator.h',
           'memory/discardable_shared_memory.cc',
           'memory/discardable_shared_memory.h',
           'memory/linked_ptr.h',
diff --git a/base/memory/BUILD.gn b/base/memory/BUILD.gn
index 3d4c22cd..a0608e8 100644
--- a/base/memory/BUILD.gn
+++ b/base/memory/BUILD.gn
@@ -8,10 +8,8 @@ source_set("memory") {
     "aligned_memory.h",
     "discardable_memory.cc",
     "discardable_memory.h",
-    "discardable_memory_shmem.cc",
-    "discardable_memory_shmem.h",
-    "discardable_memory_shmem_allocator.cc",
-    "discardable_memory_shmem_allocator.h",
+    "discardable_memory_allocator.cc",
+    "discardable_memory_allocator.h",
     "discardable_shared_memory.cc",
     "discardable_shared_memory.h",
     "linked_ptr.h",
@@ -42,10 +40,8 @@ source_set("memory") {
     sources -= [
       "discardable_memory.cc",
       "discardable_memory.h",
-      "discardable_memory_shmem.cc",
-      "discardable_memory_shmem.h",
-      "discardable_memory_shmem_allocator.cc",
-      "discardable_memory_shmem_allocator.h",
+      "discardable_memory_allocator.cc",
+      "discardable_memory_allocator.h",
       "discardable_shared_memory.cc",
       "discardable_shared_memory.h",
       "shared_memory_posix.cc",
diff --git a/base/memory/discardable_memory.cc b/base/memory/discardable_memory.cc
index 0e3b58a..a99c6f8 100644
--- a/base/memory/discardable_memory.cc
+++ b/base/memory/discardable_memory.cc
@@ -4,14 +4,15 @@
 
 #include "base/memory/discardable_memory.h"
 
-#include "base/memory/discardable_memory_shmem.h"
+#include "base/memory/discardable_memory_allocator.h"
 
 namespace base {
 
 // static
 scoped_ptr<DiscardableMemory> DiscardableMemory::CreateLockedMemory(
     size_t size) {
-  return make_scoped_ptr(new internal::DiscardableMemoryShmem(size));
+  return DiscardableMemoryAllocator::GetInstance()
+      ->AllocateLockedDiscardableMemory(size);
 }
 
 }  // namespace base
diff --git a/base/memory/discardable_memory_allocator.cc b/base/memory/discardable_memory_allocator.cc
new file mode 100644
index 0000000..002a3ba
--- /dev/null
+++ b/base/memory/discardable_memory_allocator.cc
@@ -0,0 +1,34 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/memory/discardable_memory_allocator.h"
+
+#include "base/logging.h"
+
+namespace base {
+namespace {
+
+DiscardableMemoryAllocator* g_allocator = nullptr;
+
+}  // namespace
+
+// static
+void DiscardableMemoryAllocator::SetInstance(
+    DiscardableMemoryAllocator* allocator) {
+  DCHECK(allocator);
+
+  // Make sure this function is only called once before the first call
+  // to GetInstance().
+  DCHECK(!g_allocator);
+
+  g_allocator = allocator;
+}
+
+// static
+DiscardableMemoryAllocator* DiscardableMemoryAllocator::GetInstance() {
+  DCHECK(g_allocator);
+  return g_allocator;
+}
+
+}  // namespace base
diff --git a/base/memory/discardable_memory_allocator.h b/base/memory/discardable_memory_allocator.h
new file mode 100644
index 0000000..400f87a
--- /dev/null
+++ b/base/memory/discardable_memory_allocator.h
@@ -0,0 +1,32 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_MEMORY_DISCARDABLE_MEMORY_ALLOCATOR_H_
+#define BASE_MEMORY_DISCARDABLE_MEMORY_ALLOCATOR_H_
+
+#include "base/base_export.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace base {
+class DiscardableMemory;
+
+class BASE_EXPORT DiscardableMemoryAllocator {
+ public:
+  // Returns the allocator instance.
+  static DiscardableMemoryAllocator* GetInstance();
+
+  // Sets the allocator instance. Can only be called once, e.g. on startup.
+  // Ownership of |instance| remains with the caller.
+  static void SetInstance(DiscardableMemoryAllocator* allocator);
+
+  virtual scoped_ptr<DiscardableMemory> AllocateLockedDiscardableMemory(
+      size_t size) = 0;
+
+ protected:
+  virtual ~DiscardableMemoryAllocator() {}
+};
+
+}  // namespace base
+
+#endif  // BASE_MEMORY_DISCARDABLE_MEMORY_ALLOCATOR_H_
diff --git a/base/memory/discardable_memory_shmem.cc b/base/memory/discardable_memory_shmem.cc
deleted file mode 100644
index 059d84c..0000000
--- a/base/memory/discardable_memory_shmem.cc
+++ /dev/null
@@ -1,50 +0,0 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "base/memory/discardable_memory_shmem.h"
-
-#include "base/lazy_instance.h"
-#include "base/memory/discardable_memory_shmem_allocator.h"
-
-namespace base {
-namespace internal {
-
-DiscardableMemoryShmem::DiscardableMemoryShmem(size_t bytes)
-    : chunk_(DiscardableMemoryShmemAllocator::GetInstance()
-                 ->AllocateLockedDiscardableMemory(bytes)),
-      is_locked_(true) {
-  DCHECK(chunk_);
-}
-
-DiscardableMemoryShmem::~DiscardableMemoryShmem() {
-  if (is_locked_)
-    Unlock();
-}
-
-bool DiscardableMemoryShmem::Lock() {
-  DCHECK(!is_locked_);
-  DCHECK(chunk_);
-
-  if (!chunk_->Lock()) {
-    chunk_.reset();
-    return false;
-  }
-
-  is_locked_ = true;
-  return true;
-}
-
-void DiscardableMemoryShmem::Unlock() {
-  DCHECK(is_locked_);
-  chunk_->Unlock();
-  is_locked_ = false;
-}
-
-void* DiscardableMemoryShmem::Memory() const {
-  DCHECK(is_locked_);
-  return chunk_->Memory();
-}
-
-}  // namespace internal
-}  // namespace base
diff --git a/base/memory/discardable_memory_shmem.h b/base/memory/discardable_memory_shmem.h
deleted file mode 100644
index f394562..0000000
--- a/base/memory/discardable_memory_shmem.h
+++ /dev/null
@@ -1,37 +0,0 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef BASE_MEMORY_DISCARDABLE_MEMORY_SHMEM_H_
-#define BASE_MEMORY_DISCARDABLE_MEMORY_SHMEM_H_
-
-#include "base/memory/discardable_memory.h"
-
-namespace base {
-class DiscardableMemoryShmemChunk;
-
-namespace internal {
-
-class DiscardableMemoryShmem : public DiscardableMemory {
- public:
-  explicit DiscardableMemoryShmem(size_t bytes);
-  ~DiscardableMemoryShmem() override;
-
-  bool Initialize();
-
-  // Overridden from DiscardableMemory:
-  bool Lock() override;
-  void Unlock() override;
-  void* Memory() const override;
-
- private:
-  scoped_ptr<DiscardableMemoryShmemChunk> chunk_;
-  bool is_locked_;
-
-  DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryShmem);
-};
-
-}  // namespace internal
-}  // namespace base
-
-#endif  // BASE_MEMORY_DISCARDABLE_MEMORY_SHMEM_H_
diff --git a/base/memory/discardable_memory_shmem_allocator.cc b/base/memory/discardable_memory_shmem_allocator.cc
deleted file mode 100644
index a87c58d..0000000
--- a/base/memory/discardable_memory_shmem_allocator.cc
+++ /dev/null
@@ -1,37 +0,0 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "base/memory/discardable_memory_shmem_allocator.h"
-
-#include "base/lazy_instance.h"
-#include "base/logging.h"
-#include "base/memory/discardable_shared_memory.h"
-
-namespace base {
-namespace {
-
-DiscardableMemoryShmemAllocator* g_allocator = nullptr;
-
-}  // namespace
-
-// static
-void DiscardableMemoryShmemAllocator::SetInstance(
-    DiscardableMemoryShmemAllocator* allocator) {
-  DCHECK(allocator);
-
-  // Make sure this function is only called once before the first call
-  // to GetInstance().
-  DCHECK(!g_allocator);
-
-  g_allocator = allocator;
-}
-
-// static
-DiscardableMemoryShmemAllocator*
-DiscardableMemoryShmemAllocator::GetInstance() {
-  DCHECK(g_allocator);
-  return g_allocator;
-}
-
-}  // namespace base
diff --git a/base/memory/discardable_memory_shmem_allocator.h b/base/memory/discardable_memory_shmem_allocator.h
deleted file mode 100644
index ac4118e..0000000
--- a/base/memory/discardable_memory_shmem_allocator.h
+++ /dev/null
@@ -1,42 +0,0 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef BASE_MEMORY_DISCARDABLE_MEMORY_SHMEM_ALLOCATOR_H_
-#define BASE_MEMORY_DISCARDABLE_MEMORY_SHMEM_ALLOCATOR_H_
-
-#include "base/base_export.h"
-#include "base/memory/scoped_ptr.h"
-
-namespace base {
-
-// TODO(reveman): Remove this by having allocator interface return
-// real DiscardableMemory instances. crbug.com/442945
-class BASE_EXPORT DiscardableMemoryShmemChunk {
- public:
-  virtual ~DiscardableMemoryShmemChunk() {}
-
-  virtual bool Lock() = 0;
-  virtual void Unlock() = 0;
-  virtual void* Memory() const = 0;
-};
-
-class BASE_EXPORT DiscardableMemoryShmemAllocator {
- public:
-  // Returns the allocator instance.
-  static DiscardableMemoryShmemAllocator* GetInstance();
-
-  // Sets the allocator instance. Can only be called once, e.g. on startup.
-  // Ownership of |instance| remains with the caller.
-  static void SetInstance(DiscardableMemoryShmemAllocator* allocator);
-
-  virtual scoped_ptr<DiscardableMemoryShmemChunk>
-  AllocateLockedDiscardableMemory(size_t size) = 0;
-
- protected:
-  virtual ~DiscardableMemoryShmemAllocator() {}
-};
-
-}  // namespace base
-
-#endif  // BASE_MEMORY_DISCARDABLE_MEMORY_SHMEM_ALLOCATOR_H_
diff --git a/base/test/BUILD.gn b/base/test/BUILD.gn
index f5d2e4c..c4356cb 100644
--- a/base/test/BUILD.gn
+++ b/base/test/BUILD.gn
@@ -81,8 +81,8 @@ source_set("test_support") {
     "simple_test_tick_clock.h",
     "task_runner_test_template.cc",
     "task_runner_test_template.h",
-    "test_discardable_memory_shmem_allocator.cc",
-    "test_discardable_memory_shmem_allocator.h",
+    "test_discardable_memory_allocator.cc",
+    "test_discardable_memory_allocator.h",
     "test_file_util.cc",
     "test_file_util.h",
     "test_file_util_android.cc",
diff --git a/base/test/test_discardable_memory_allocator.cc b/base/test/test_discardable_memory_allocator.cc
new file mode 100644
index 0000000..cb2cccf
--- /dev/null
+++ b/base/test/test_discardable_memory_allocator.cc
@@ -0,0 +1,40 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/test/test_discardable_memory_allocator.h"
+
+#include <stdint.h>
+
+#include "base/memory/discardable_memory.h"
+
+namespace base {
+namespace {
+
+class DiscardableMemoryImpl : public DiscardableMemory {
+ public:
+  explicit DiscardableMemoryImpl(size_t size) : memory_(new uint8_t[size]) {}
+
+  // Overridden from DiscardableMemory:
+  bool Lock() override { return false; }
+  void Unlock() override {}
+  void* Memory() const override { return memory_.get(); }
+
+ private:
+  scoped_ptr<uint8_t[]> memory_;
+};
+
+}  // namespace
+
+TestDiscardableMemoryAllocator::TestDiscardableMemoryAllocator() {
+}
+
+TestDiscardableMemoryAllocator::~TestDiscardableMemoryAllocator() {
+}
+
+scoped_ptr<DiscardableMemory>
+TestDiscardableMemoryAllocator::AllocateLockedDiscardableMemory(size_t size) {
+  return make_scoped_ptr(new DiscardableMemoryImpl(size));
+}
+
+}  // namespace base
diff --git a/base/test/test_discardable_memory_allocator.h b/base/test/test_discardable_memory_allocator.h
new file mode 100644
index 0000000..df9d469
--- /dev/null
+++ b/base/test/test_discardable_memory_allocator.h
@@ -0,0 +1,30 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_TEST_TEST_DISCARDABLE_MEMORY_ALLOCATOR_H_
+#define BASE_TEST_TEST_DISCARDABLE_MEMORY_ALLOCATOR_H_
+
+#include "base/memory/discardable_memory_allocator.h"
+
+namespace base {
+
+// TestDiscardableMemoryAllocator is a simple DiscardableMemoryAllocator
+// implementation that can be used for testing. It allocates one-shot
+// DiscardableMemory instances backed by heap memory.
+class TestDiscardableMemoryAllocator : public DiscardableMemoryAllocator {
+ public:
+  TestDiscardableMemoryAllocator();
+  ~TestDiscardableMemoryAllocator() override;
+
+  // Overridden from DiscardableMemoryAllocator:
+  scoped_ptr<DiscardableMemory> AllocateLockedDiscardableMemory(
+      size_t size) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestDiscardableMemoryAllocator);
+};
+
+}  // namespace base
+
+#endif  // BASE_TEST_TEST_DISCARDABLE_MEMORY_ALLOCATOR_H_
diff --git a/base/test/test_discardable_memory_shmem_allocator.cc b/base/test/test_discardable_memory_shmem_allocator.cc
deleted file mode 100644
index 24185a2..0000000
--- a/base/test/test_discardable_memory_shmem_allocator.cc
+++ /dev/null
@@ -1,40 +0,0 @@
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "base/test/test_discardable_memory_shmem_allocator.h"
-
-#include <stdint.h>
-
-namespace base {
-namespace {
-
-class DiscardableMemoryShmemChunkImpl : public DiscardableMemoryShmemChunk {
- public:
-  explicit DiscardableMemoryShmemChunkImpl(size_t size)
-      : memory_(new uint8_t[size]) {}
-
-  // Overridden from DiscardableMemoryShmemChunk:
-  bool Lock() override { return false; }
-  void Unlock() override {}
-  void* Memory() const override { return memory_.get(); }
-
- private:
-  scoped_ptr<uint8_t[]> memory_;
-};
-
-}  // namespace
-
-TestDiscardableMemoryShmemAllocator::TestDiscardableMemoryShmemAllocator() {
-}
-
-TestDiscardableMemoryShmemAllocator::~TestDiscardableMemoryShmemAllocator() {
-}
-
-scoped_ptr<DiscardableMemoryShmemChunk>
-TestDiscardableMemoryShmemAllocator::AllocateLockedDiscardableMemory(
-    size_t size) {
-  return make_scoped_ptr(new DiscardableMemoryShmemChunkImpl(size));
-}
-
-}  // namespace base
diff --git a/base/test/test_discardable_memory_shmem_allocator.h b/base/test/test_discardable_memory_shmem_allocator.h
deleted file mode 100644
index a40960e..0000000
--- a/base/test/test_discardable_memory_shmem_allocator.h
+++ /dev/null
@@ -1,28 +0,0 @@
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef BASE_TEST_TEST_DISCARDABLE_MEMORY_SHMEM_ALLOCATOR_H_
-#define BASE_TEST_TEST_DISCARDABLE_MEMORY_SHMEM_ALLOCATOR_H_
-
-#include "base/memory/discardable_memory_shmem_allocator.h"
-
-namespace base {
-
-class TestDiscardableMemoryShmemAllocator
-    : public DiscardableMemoryShmemAllocator {
- public:
-  TestDiscardableMemoryShmemAllocator();
-  ~TestDiscardableMemoryShmemAllocator() override;
-
-  // Overridden from DiscardableMemoryShmemAllocator:
-  scoped_ptr<DiscardableMemoryShmemChunk> AllocateLockedDiscardableMemory(
-      size_t size) override;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(TestDiscardableMemoryShmemAllocator);
-};
-
-}  // namespace base
-
-#endif  // BASE_TEST_TEST_DISCARDABLE_MEMORY_SHMEM_ALLOCATOR_H_
diff --git a/chrome/test/base/chrome_unit_test_suite.cc b/chrome/test/base/chrome_unit_test_suite.cc
index 2ce04bd..a1dd475 100644
--- a/chrome/test/base/chrome_unit_test_suite.cc
+++ b/chrome/test/base/chrome_unit_test_suite.cc
@@ -111,8 +111,7 @@ void ChromeUnitTestSuite::Initialize() {
   // intialization which calls base's which initializes ICU.
   InitializeResourceBundle();
 
-  base::DiscardableMemoryShmemAllocator::SetInstance(
-      &discardable_memory_allocator_);
+  base::DiscardableMemoryAllocator::SetInstance(&discardable_memory_allocator_);
 }
 
 void ChromeUnitTestSuite::Shutdown() {
diff --git a/chrome/test/base/chrome_unit_test_suite.h b/chrome/test/base/chrome_unit_test_suite.h
index 404c59f..5a92bc7 100644
--- a/chrome/test/base/chrome_unit_test_suite.h
+++ b/chrome/test/base/chrome_unit_test_suite.h
@@ -8,7 +8,7 @@
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/files/file_path.h"
-#include "base/test/test_discardable_memory_shmem_allocator.h"
+#include "base/test/test_discardable_memory_allocator.h"
 #include "chrome/test/base/chrome_test_suite.h"
 
 // Test suite for unit tests. Creates additional stub services that are not
@@ -29,7 +29,7 @@ class ChromeUnitTestSuite : public ChromeTestSuite {
   static void InitializeResourceBundle();
 
  private:
-  base::TestDiscardableMemoryShmemAllocator discardable_memory_allocator_;
+  base::TestDiscardableMemoryAllocator discardable_memory_allocator_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeUnitTestSuite);
 };
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index bf495b9..2a56518 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -461,7 +461,7 @@ void BrowserMainLoop::EarlyInitialization() {
       gfx::GpuMemoryBuffer::SCANOUT);
 #endif
 
-  base::DiscardableMemoryShmemAllocator::SetInstance(
+  base::DiscardableMemoryAllocator::SetInstance(
       HostDiscardableSharedMemoryManager::current());
 
   if (parts_)
diff --git a/content/child/child_discardable_shared_memory_manager.cc b/content/child/child_discardable_shared_memory_manager.cc
index 86822a2..335a423 100644
--- a/content/child/child_discardable_shared_memory_manager.cc
+++ b/content/child/child_discardable_shared_memory_manager.cc
@@ -7,6 +7,7 @@
 #include "base/atomic_sequence_num.h"
 #include "base/bind.h"
 #include "base/debug/crash_logging.h"
+#include "base/memory/discardable_memory.h"
 #include "base/memory/discardable_shared_memory.h"
 #include "base/metrics/histogram.h"
 #include "base/process/process_metrics.h"
@@ -28,29 +29,46 @@ const size_t kAllocationSize = 4 * 1024 * 1024;
 // Global atomic to generate unique discardable shared memory IDs.
 base::StaticAtomicSequenceNumber g_next_discardable_shared_memory_id;
 
-class DiscardableMemoryShmemChunkImpl
-    : public base::DiscardableMemoryShmemChunk {
+class DiscardableMemoryImpl : public base::DiscardableMemory {
  public:
-  DiscardableMemoryShmemChunkImpl(
-      ChildDiscardableSharedMemoryManager* manager,
-      scoped_ptr<DiscardableSharedMemoryHeap::Span> span)
-      : manager_(manager), span_(span.Pass()) {}
-  ~DiscardableMemoryShmemChunkImpl() override {
+  DiscardableMemoryImpl(ChildDiscardableSharedMemoryManager* manager,
+                        scoped_ptr<DiscardableSharedMemoryHeap::Span> span)
+      : manager_(manager), span_(span.Pass()), is_locked_(true) {}
+
+  ~DiscardableMemoryImpl() override {
+    if (is_locked_)
+      manager_->UnlockSpan(span_.get());
+
     manager_->ReleaseSpan(span_.Pass());
   }
 
-  // Overridden from DiscardableMemoryShmemChunk:
-  bool Lock() override { return manager_->LockSpan(span_.get()); }
-  void Unlock() override { manager_->UnlockSpan(span_.get()); }
+  // Overridden from base::DiscardableMemory:
+  bool Lock() override {
+    DCHECK(!is_locked_);
+
+    if (!manager_->LockSpan(span_.get()))
+      return false;
+
+    is_locked_ = true;
+    return true;
+  }
+  void Unlock() override {
+    DCHECK(is_locked_);
+
+    manager_->UnlockSpan(span_.get());
+    is_locked_ = false;
+  }
   void* Memory() const override {
+    DCHECK(is_locked_);
     return reinterpret_cast<void*>(span_->start() * base::GetPageSize());
   }
 
  private:
-  ChildDiscardableSharedMemoryManager* manager_;
+  ChildDiscardableSharedMemoryManager* const manager_;
   scoped_ptr<DiscardableSharedMemoryHeap::Span> span_;
+  bool is_locked_;
 
-  DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryShmemChunkImpl);
+  DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryImpl);
 };
 
 }  // namespace
@@ -70,7 +88,7 @@ ChildDiscardableSharedMemoryManager::~ChildDiscardableSharedMemoryManager() {
     MemoryUsageChanged(0, 0);
 }
 
-scoped_ptr<base::DiscardableMemoryShmemChunk>
+scoped_ptr<base::DiscardableMemory>
 ChildDiscardableSharedMemoryManager::AllocateLockedDiscardableMemory(
     size_t size) {
   base::AutoLock lock(lock_);
@@ -124,8 +142,7 @@ ChildDiscardableSharedMemoryManager::AllocateLockedDiscardableMemory(
     // at least one span from the free lists.
     MemoryUsageChanged(heap_.GetSize(), heap_.GetSizeOfFreeLists());
 
-    return make_scoped_ptr(
-        new DiscardableMemoryShmemChunkImpl(this, free_span.Pass()));
+    return make_scoped_ptr(new DiscardableMemoryImpl(this, free_span.Pass()));
   }
 
   // Release purged memory to free up the address space before we attempt to
@@ -167,8 +184,7 @@ ChildDiscardableSharedMemoryManager::AllocateLockedDiscardableMemory(
 
   MemoryUsageChanged(heap_.GetSize(), heap_.GetSizeOfFreeLists());
 
-  return make_scoped_ptr(
-      new DiscardableMemoryShmemChunkImpl(this, new_span.Pass()));
+  return make_scoped_ptr(new DiscardableMemoryImpl(this, new_span.Pass()));
 }
 
 void ChildDiscardableSharedMemoryManager::ReleaseFreeMemory() {
diff --git a/content/child/child_discardable_shared_memory_manager.h b/content/child/child_discardable_shared_memory_manager.h
index 518f72b..3dee173 100644
--- a/content/child/child_discardable_shared_memory_manager.h
+++ b/content/child/child_discardable_shared_memory_manager.h
@@ -5,7 +5,7 @@
 #ifndef CONTENT_CHILD_CHILD_DISCARDABLE_SHARED_MEMORY_MANAGER_H_
 #define CONTENT_CHILD_CHILD_DISCARDABLE_SHARED_MEMORY_MANAGER_H_
 
-#include "base/memory/discardable_memory_shmem_allocator.h"
+#include "base/memory/discardable_memory_allocator.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
@@ -16,16 +16,16 @@
 
 namespace content {
 
-// Implementation of DiscardableMemoryShmemAllocator that allocates
+// Implementation of DiscardableMemoryAllocator that allocates
 // discardable memory segments through the browser process.
 class CONTENT_EXPORT ChildDiscardableSharedMemoryManager
-    : public base::DiscardableMemoryShmemAllocator {
+    : public base::DiscardableMemoryAllocator {
  public:
   explicit ChildDiscardableSharedMemoryManager(ThreadSafeSender* sender);
   ~ChildDiscardableSharedMemoryManager() override;
 
-  // Overridden from base::DiscardableMemoryShmemAllocator:
-  scoped_ptr<base::DiscardableMemoryShmemChunk> AllocateLockedDiscardableMemory(
+  // Overridden from base::DiscardableMemoryAllocator:
+  scoped_ptr<base::DiscardableMemory> AllocateLockedDiscardableMemory(
       size_t size) override;
 
   // Release memory and associated resources that have been purged.
diff --git a/content/child/child_discardable_shared_memory_manager_browsertest.cc b/content/child/child_discardable_shared_memory_manager_browsertest.cc
index 813c55d..1764cb0 100644
--- a/content/child/child_discardable_shared_memory_manager_browsertest.cc
+++ b/content/child/child_discardable_shared_memory_manager_browsertest.cc
@@ -4,6 +4,7 @@
 
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "base/memory/discardable_memory.h"
 #include "content/child/child_discardable_shared_memory_manager.h"
 #include "content/child/child_thread_impl.h"
 #include "content/common/host_discardable_shared_memory_manager.h"
@@ -30,23 +31,21 @@ class ChildDiscardableSharedMemoryManagerBrowserTest
 
   static void AllocateLockedMemory(
       size_t size,
-      scoped_ptr<base::DiscardableMemoryShmemChunk>* memory) {
+      scoped_ptr<base::DiscardableMemory>* memory) {
     *memory = ChildThreadImpl::current()
                   ->discardable_shared_memory_manager()
                   ->AllocateLockedDiscardableMemory(size);
   }
 
-  static void LockMemory(base::DiscardableMemoryShmemChunk* memory,
-                         bool* result) {
+  static void LockMemory(base::DiscardableMemory* memory, bool* result) {
     *result = memory->Lock();
   }
 
-  static void UnlockMemory(base::DiscardableMemoryShmemChunk* memory) {
+  static void UnlockMemory(base::DiscardableMemory* memory) {
     memory->Unlock();
   }
 
-  static void FreeMemory(scoped_ptr<base::DiscardableMemoryShmemChunk> memory) {
-  }
+  static void FreeMemory(scoped_ptr<base::DiscardableMemory> memory) {}
 };
 
 IN_PROC_BROWSER_TEST_F(ChildDiscardableSharedMemoryManagerBrowserTest,
@@ -55,7 +54,7 @@ IN_PROC_BROWSER_TEST_F(ChildDiscardableSharedMemoryManagerBrowserTest,
 
   NavigateToURL(shell(), GURL(url::kAboutBlankURL));
 
-  scoped_ptr<base::DiscardableMemoryShmemChunk> memory;
+  scoped_ptr<base::DiscardableMemory> memory;
   PostTaskToInProcessRendererAndWait(base::Bind(
       &ChildDiscardableSharedMemoryManagerBrowserTest::AllocateLockedMemory,
       kSize, &memory));
@@ -91,7 +90,7 @@ IN_PROC_BROWSER_TEST_F(ChildDiscardableSharedMemoryManagerBrowserTest,
 
   NavigateToURL(shell(), GURL(url::kAboutBlankURL));
 
-  scoped_ptr<base::DiscardableMemoryShmemChunk> instances[kNumberOfInstances];
+  scoped_ptr<base::DiscardableMemory> instances[kNumberOfInstances];
   for (auto& memory : instances) {
     PostTaskToInProcessRendererAndWait(base::Bind(
         &ChildDiscardableSharedMemoryManagerBrowserTest::AllocateLockedMemory,
@@ -117,7 +116,7 @@ IN_PROC_BROWSER_TEST_F(ChildDiscardableSharedMemoryManagerBrowserTest,
 
   NavigateToURL(shell(), GURL(url::kAboutBlankURL));
 
-  scoped_ptr<base::DiscardableMemoryShmemChunk> memory;
+  scoped_ptr<base::DiscardableMemory> memory;
   PostTaskToInProcessRendererAndWait(base::Bind(
       &ChildDiscardableSharedMemoryManagerBrowserTest::AllocateLockedMemory,
       kSize, &memory));
diff --git a/content/common/host_discardable_shared_memory_manager.cc b/content/common/host_discardable_shared_memory_manager.cc
index ab74ef0..c4fea8d 100644
--- a/content/common/host_discardable_shared_memory_manager.cc
+++ b/content/common/host_discardable_shared_memory_manager.cc
@@ -11,6 +11,7 @@
 #include "base/callback.h"
 #include "base/debug/crash_logging.h"
 #include "base/lazy_instance.h"
+#include "base/memory/discardable_memory.h"
 #include "base/numerics/safe_math.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/strings/string_number_conversions.h"
@@ -20,23 +21,22 @@
 namespace content {
 namespace {
 
-class DiscardableMemoryShmemChunkImpl
-    : public base::DiscardableMemoryShmemChunk {
+class DiscardableMemoryImpl : public base::DiscardableMemory {
  public:
-  DiscardableMemoryShmemChunkImpl(
-      scoped_ptr<base::DiscardableSharedMemory> shared_memory,
-      const base::Closure& deleted_callback)
+  DiscardableMemoryImpl(scoped_ptr<base::DiscardableSharedMemory> shared_memory,
+                        const base::Closure& deleted_callback)
       : shared_memory_(shared_memory.Pass()),
         deleted_callback_(deleted_callback),
         is_locked_(true) {}
-  ~DiscardableMemoryShmemChunkImpl() override {
+
+  ~DiscardableMemoryImpl() override {
     if (is_locked_)
       shared_memory_->Unlock(0, 0);
 
     deleted_callback_.Run();
   }
 
-  // Overridden from base::DiscardableMemoryShmemChunk:
+  // Overridden from base::DiscardableMemory:
   bool Lock() override {
     DCHECK(!is_locked_);
 
@@ -62,7 +62,7 @@ class DiscardableMemoryShmemChunkImpl
   const base::Closure deleted_callback_;
   bool is_locked_;
 
-  DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryShmemChunkImpl);
+  DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryImpl);
 };
 
 base::LazyInstance<HostDiscardableSharedMemoryManager>
@@ -107,7 +107,7 @@ HostDiscardableSharedMemoryManager::current() {
   return g_discardable_shared_memory_manager.Pointer();
 }
 
-scoped_ptr<base::DiscardableMemoryShmemChunk>
+scoped_ptr<base::DiscardableMemory>
 HostDiscardableSharedMemoryManager::AllocateLockedDiscardableMemory(
     size_t size) {
   DiscardableSharedMemoryId new_id =
@@ -123,7 +123,7 @@ HostDiscardableSharedMemoryManager::AllocateLockedDiscardableMemory(
   scoped_ptr<base::DiscardableSharedMemory> memory(
       new base::DiscardableSharedMemory(handle));
   CHECK(memory->Map(size));
-  return make_scoped_ptr(new DiscardableMemoryShmemChunkImpl(
+  return make_scoped_ptr(new DiscardableMemoryImpl(
       memory.Pass(),
       base::Bind(
           &HostDiscardableSharedMemoryManager::DeletedDiscardableSharedMemory,
diff --git a/content/common/host_discardable_shared_memory_manager.h b/content/common/host_discardable_shared_memory_manager.h
index 36de71d..f68ed93 100644
--- a/content/common/host_discardable_shared_memory_manager.h
+++ b/content/common/host_discardable_shared_memory_manager.h
@@ -8,7 +8,7 @@
 #include <vector>
 
 #include "base/containers/hash_tables.h"
-#include "base/memory/discardable_memory_shmem_allocator.h"
+#include "base/memory/discardable_memory_allocator.h"
 #include "base/memory/discardable_shared_memory.h"
 #include "base/memory/memory_pressure_listener.h"
 #include "base/memory/ref_counted.h"
@@ -21,12 +21,11 @@
 namespace content {
 typedef int32_t DiscardableSharedMemoryId;
 
-// Implementation of DiscardableMemoryShmemAllocator that allocates and
-// manages discardable memory segments for the browser process and child
-// processes. This class is thread-safe and instances can safely be used
-// on any thread.
+// Implementation of DiscardableMemoryAllocator that allocates and manages
+// discardable memory segments for the browser process and child processes.
+// This class is thread-safe and instances can safely be used on any thread.
 class CONTENT_EXPORT HostDiscardableSharedMemoryManager
-    : public base::DiscardableMemoryShmemAllocator {
+    : public base::DiscardableMemoryAllocator {
  public:
   HostDiscardableSharedMemoryManager();
   ~HostDiscardableSharedMemoryManager() override;
@@ -34,8 +33,8 @@ class CONTENT_EXPORT HostDiscardableSharedMemoryManager
   // Returns a singleton instance.
   static HostDiscardableSharedMemoryManager* current();
 
-  // Overridden from base::DiscardableMemoryShmemAllocator:
-  scoped_ptr<base::DiscardableMemoryShmemChunk> AllocateLockedDiscardableMemory(
+  // Overridden from base::DiscardableMemoryAllocator:
+  scoped_ptr<base::DiscardableMemory> AllocateLockedDiscardableMemory(
       size_t size) override;
 
   // This allocates a discardable memory segment for |process_handle|.
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index d8f7974..f9d02f1 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -13,8 +13,7 @@
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
-#include "base/memory/discardable_memory.h"
-#include "base/memory/discardable_memory_shmem_allocator.h"
+#include "base/memory/discardable_memory_allocator.h"
 #include "base/memory/shared_memory.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
@@ -659,7 +658,7 @@ void RenderThreadImpl::Init() {
   // In single process, browser main loop set up the discardable memory
   // allocator.
   if (!command_line.HasSwitch(switches::kSingleProcess)) {
-    base::DiscardableMemoryShmemAllocator::SetInstance(
+    base::DiscardableMemoryAllocator::SetInstance(
         ChildThreadImpl::discardable_shared_memory_manager());
   }
 
diff --git a/content/test/blink_test_environment.cc b/content/test/blink_test_environment.cc
index 16b35a6..c20e986 100644
--- a/content/test/blink_test_environment.cc
+++ b/content/test/blink_test_environment.cc
@@ -10,7 +10,7 @@
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/strings/string_tokenizer.h"
-#include "base/test/test_discardable_memory_shmem_allocator.h"
+#include "base/test/test_discardable_memory_allocator.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/user_agent.h"
@@ -69,7 +69,7 @@ class TestEnvironment {
     blink_test_support_.reset(new TestBlinkWebUnitTestSupport);
     content_initializer_.reset(new content::TestContentClientInitializer());
 
-    base::DiscardableMemoryShmemAllocator::SetInstance(
+    base::DiscardableMemoryAllocator::SetInstance(
         &discardable_memory_allocator_);
   }
 
@@ -84,7 +84,7 @@ class TestEnvironment {
   scoped_ptr<MessageLoopType> main_message_loop_;
   scoped_ptr<TestBlinkWebUnitTestSupport> blink_test_support_;
   scoped_ptr<TestContentClientInitializer> content_initializer_;
-  base::TestDiscardableMemoryShmemAllocator discardable_memory_allocator_;
+  base::TestDiscardableMemoryAllocator discardable_memory_allocator_;
 };
 
 TestEnvironment* test_environment;
diff --git a/ui/app_list/test/run_all_unittests.cc b/ui/app_list/test/run_all_unittests.cc
index 5da865b..07d09cb 100644
--- a/ui/app_list/test/run_all_unittests.cc
+++ b/ui/app_list/test/run_all_unittests.cc
@@ -7,7 +7,7 @@
 #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_discardable_memory_allocator.h"
 #include "base/test/test_suite.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/base/resource/resource_bundle.h"
@@ -42,7 +42,7 @@ class AppListTestSuite : public base::TestSuite {
     ASSERT_TRUE(PathService::Get(ui::UI_TEST_PAK, &ui_test_pak_path));
     ui::ResourceBundle::InitSharedInstanceWithPakPath(ui_test_pak_path);
 
-    base::DiscardableMemoryShmemAllocator::SetInstance(
+    base::DiscardableMemoryAllocator::SetInstance(
         &discardable_memory_allocator_);
   }
 
@@ -52,7 +52,7 @@ class AppListTestSuite : public base::TestSuite {
   }
 
  private:
-  base::TestDiscardableMemoryShmemAllocator discardable_memory_allocator_;
+  base::TestDiscardableMemoryAllocator discardable_memory_allocator_;
 
   DISALLOW_COPY_AND_ASSIGN(AppListTestSuite);
 };
diff --git a/ui/message_center/test/run_all_unittests.cc b/ui/message_center/test/run_all_unittests.cc
index b0cc026..019df50 100644
--- a/ui/message_center/test/run_all_unittests.cc
+++ b/ui/message_center/test/run_all_unittests.cc
@@ -7,7 +7,7 @@
 #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_discardable_memory_allocator.h"
 #include "base/test/test_suite.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/base/resource/resource_bundle.h"
@@ -39,7 +39,7 @@ class MessageCenterTestSuite : public base::TestSuite {
     ASSERT_TRUE(PathService::Get(ui::UI_TEST_PAK, &ui_test_pak_path));
     ui::ResourceBundle::InitSharedInstanceWithPakPath(ui_test_pak_path);
 
-    base::DiscardableMemoryShmemAllocator::SetInstance(
+    base::DiscardableMemoryAllocator::SetInstance(
         &discardable_memory_allocator_);
   }
 
@@ -49,7 +49,7 @@ class MessageCenterTestSuite : public base::TestSuite {
   }
 
  private:
-  base::TestDiscardableMemoryShmemAllocator discardable_memory_allocator_;
+  base::TestDiscardableMemoryAllocator discardable_memory_allocator_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageCenterTestSuite);
 };