Replace blink::WebDiscardableMemory with base::DiscardableMemory.

base/test/test_discardable_memory_allocator.cc

 // 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 <cstdint>
+#include <cstring>
 
 #include "base/memory/discardable_memory.h"
 
 namespace base {
 namespace {
 
 class DiscardableMemoryImpl : public DiscardableMemory {
  public:
-  explicit DiscardableMemoryImpl(size_t size) : data_(new uint8_t[size]) {}
+  explicit DiscardableMemoryImpl(size_t size)
+      : data_(new uint8_t[size]), size_(size) {}
 
   // Overridden from DiscardableMemory:
-  bool Lock() override { return false; }
-  void Unlock() override {}
-  void* data() const override { return data_.get(); }
+  bool Lock() override {
+    DCHECK(!is_locked_);
+    is_locked_ = true;
+    return false;
+  }
+
+  void Unlock() override {
+    DCHECK(is_locked_);
+    is_locked_ = false;
+    // Force eviction to catch clients not correctly checking the return value
+    // of Lock().
+    memset(data_.get(), 0, size_);
+  }
+
+  void* data() const override {
+    DCHECK(is_locked_);
+    return data_.get();
+  }
 
   trace_event::MemoryAllocatorDump* CreateMemoryAllocatorDump(
       const char* name,
       trace_event::ProcessMemoryDump* pmd) const override {
     return nullptr;
   }
 
  private:
+  bool is_locked_ = true;
   scoped_ptr<uint8_t[]> data_;
+  size_t size_;
 };
 
 }  // namespace
 
 TestDiscardableMemoryAllocator::TestDiscardableMemoryAllocator() {
 }
 
 TestDiscardableMemoryAllocator::~TestDiscardableMemoryAllocator() {
 }
 
 scoped_ptr<DiscardableMemory>
 TestDiscardableMemoryAllocator::AllocateLockedDiscardableMemory(size_t size) {
   return make_scoped_ptr(new DiscardableMemoryImpl(size));
 }
 
 }  // namespace base