Revert of discardable_memory: Using mojo IPC to replace Chrome IPC

content/common/child_process_messages.h

Index: content/common/child_process_messages.h
diff --git a/content/common/child_process_messages.h b/content/common/child_process_messages.h
index 9da6914a56089f534600d66d099bcd031c7a2da8..fefc94fcfc6ac8ead7f12db09867466fcd785370 100644
--- a/content/common/child_process_messages.h
+++ b/content/common/child_process_messages.h
@@ -15,6 +15,7 @@
 #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"
@@ -204,6 +205,19 @@
                      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,