Revert of discardable_memory: Using mojo IPC to replace Chrome IPC

content/common/child_process_messages.h

 // Copyright (c) 2012 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.
 
 // Common IPC messages used for child processes.
 // Multiply-included message file, hence no include guard.
 
 #include <stdint.h>
 
 #include <string>
 #include <vector>
 
 #include "base/memory/shared_memory.h"
 #include "base/tracked_objects.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "cc/resources/shared_bitmap_manager.h"
+#include "components/discardable_memory/common/discardable_shared_memory_id.h"
 #include "content/common/content_export.h"
 #include "content/common/content_param_traits_macros.h"
 #include "gpu/command_buffer/common/sync_token.h"
 #include "gpu/ipc/common/gpu_param_traits_macros.h"
 #include "ipc/ipc_channel_handle.h"
 #include "ipc/ipc_message_macros.h"
 #include "ipc/ipc_platform_file.h"
 #include "ui/gfx/gpu_memory_buffer.h"
 #include "ui/gfx/ipc/gfx_param_traits.h"
 #include "ui/gfx/ipc/skia/gfx_skia_param_traits.h"
@@ skipping 169 matching lines @@
                             uint32_t /* height */,
                             gfx::BufferFormat,
                             gfx::BufferUsage,
                             gfx::GpuMemoryBufferHandle)
 
 // Informs the browser that the child deleted a gpu memory buffer.
 IPC_MESSAGE_CONTROL2(ChildProcessHostMsg_DeletedGpuMemoryBuffer,
                      gfx::GpuMemoryBufferId,
                      gpu::SyncToken /* sync_token */)
 
+// Asks the browser to create a block of discardable shared memory for the
+// child process.
+IPC_SYNC_MESSAGE_CONTROL2_1(
+    ChildProcessHostMsg_SyncAllocateLockedDiscardableSharedMemory,
+    uint32_t /* size */,
+    discardable_memory::DiscardableSharedMemoryId,
+    base::SharedMemoryHandle)
+
+// Informs the browser that the child deleted a block of discardable shared
+// memory.
+IPC_MESSAGE_CONTROL1(ChildProcessHostMsg_DeletedDiscardableSharedMemory,
+                     discardable_memory::DiscardableSharedMemoryId)
+
 #if defined(OS_LINUX)
 // Asks the browser to change the priority of thread.
 IPC_MESSAGE_CONTROL2(ChildProcessHostMsg_SetThreadPriority,
                      base::PlatformThreadId,
                      base::ThreadPriority)
 #endif