Replace base::SharedMemory read-only methods with GetReadOnlyHandle.

mojo/edk/embedder/platform_shared_buffer.cc

Index: mojo/edk/embedder/platform_shared_buffer.cc
diff --git a/mojo/edk/embedder/platform_shared_buffer.cc b/mojo/edk/embedder/platform_shared_buffer.cc
index 514cbeb523f9441a34d23cf96f967577e4139d06..a6121503f244ee02bfd1d05538163d6721a43ef6 100644
--- a/mojo/edk/embedder/platform_shared_buffer.cc
+++ b/mojo/edk/embedder/platform_shared_buffer.cc
@@ -204,13 +204,11 @@ PlatformSharedBuffer* PlatformSharedBuffer::CreateReadOnlyDuplicate() {
   }
 
   base::SharedMemoryHandle handle;
-  bool success;
   {
     base::AutoLock locker(lock_);
-    success = shared_memory_->ShareReadOnlyToProcess(
-        base::GetCurrentProcessHandle(), &handle);
+    handle = shared_memory_->GetReadOnlyHandle();
   }
-  if (!success || !handle.IsValid())
+  if (!handle.IsValid())
     return nullptr;
 
   return CreateFromSharedMemoryHandle(num_bytes_, true, handle);