wayland fuzzer: upgrade SharedMemory api

The fuzzer uses the shared memory API to create a file descriptor
(Harness::GetFileDescriptor). This change updates that creation from
the legacy shared memory API to the new one. There is no functional
change.

Bug: 795291
Change-Id: I186fc316c15c19fea08b04b76d8c663cdb673eb2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1695410Reviewed-by: Nic Hollingum <hollingum@google.com>
Commit-Queue: Matthew Cary (CET) <mattcary@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676303}

components/exo/wayland/fuzzer/harness.cc.tmpl

@@ -211,12 +211,14 @@ void Harness::Run(const actions::action& current_step) {
 
 int Harness::GetFileDescriptor(int id) {
   if (shared_memory_map_.count(id) == 0) {
-    auto shared_mem = std::make_unique<base::SharedMemory>();
-    shared_mem->CreateAndMapAnonymous(1);
-    shared_memory_map_.emplace(id, std::move(shared_mem));
+    base::UnsafeSharedMemoryRegion region = 
+        base::UnsafeSharedMemoryRegion::Create(1);
+    shared_memory_map_.emplace(id, std::move(region));
   }
-  return base::SharedMemory::GetFdFromSharedMemoryHandle(
-    base::SharedMemory::DuplicateHandle(shared_memory_map_[id]->handle()));
+  base::subtle::ScopedFDPair fd_pair = 
+      base::UnsafeSharedMemoryRegion::TakeHandleForSerialization(
+          shared_memory_map_[id].Duplicate()).PassPlatformHandle();
+  return fd_pair.fd.release();
 }
 
 }  // namespace wayland_fuzzer

components/exo/wayland/fuzzer/harness.h.tmpl

@@ -10,7 +10,7 @@
 
 #include <wayland-util.h>
 #include "base/macros.h"
-#include "base/memory/shared_memory.h"
+#include "base/memory/unsafe_shared_memory_region.h"
 #include "components/exo/wayland/fuzzer/actions.pb.h"
 
 // Forwards declarations for the wayland-defined structs.
@@ -60,7 +60,7 @@ class Harness {
   int GetFileDescriptor(int id);
 
  private:
-  std::map<int, std::unique_ptr<base::SharedMemory>> shared_memory_map_;
+  std::map<int, base::UnsafeSharedMemoryRegion> shared_memory_map_;
 
   DISALLOW_COPY_AND_ASSIGN(Harness);
 };