fuchsia: Set up for 3-sided roll to convert Magenta->Zircon

Fuchsia changed their kernel name from Magenta to Zircon and all the
functions and defines along with it. In order to be able to roll the SDK
in Chromium, we first need to land with this define added in v8, so that
can roll in to Chromium, then roll the Fuchsia SDK with this magic
define set (CHROMIUM_ROLLING_MAGENTA_TO_ZIRCON), then actually update v8
to reference zx_ instead of mx_ and roll that again.

Chromium-side for reference: https://chromium-review.googlesource.com/c/chromium/src/+/669139

Bug: chromium:765754, chromium:707030
Change-Id: I4ed5027f455d2346f431e7c700e87693348d5b79
Reviewed-on: https://chromium-review.googlesource.com/668751Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48047}

src/base/platform/platform-fuchsia.cc

@@ -2,8 +2,28 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// TODO(scottmg): Temporary during 3-sided roll, see https://crbug.com/765754.
+#if defined(CHROMIUM_ROLLING_MAGENTA_TO_ZIRCON)
+#include <zircon/process.h>
+#include <zircon/syscalls.h>
+#define MX_OK ZX_OK
+#define MX_PROP_NAME ZX_PROP_NAME
+#define MX_VM_FLAG_PERM_EXECUTE ZX_VM_FLAG_PERM_EXECUTE
+#define MX_VM_FLAG_PERM_READ ZX_VM_FLAG_PERM_READ
+#define MX_VM_FLAG_PERM_WRITE ZX_VM_FLAG_PERM_WRITE
+#define mx_handle_close zx_handle_close
+#define mx_handle_t zx_handle_t
+#define mx_object_set_property zx_object_set_property
+#define mx_status_t zx_status_t
+#define mx_vmar_map zx_vmar_map
+#define mx_vmar_protect zx_vmar_protect
+#define mx_vmar_root_self zx_vmar_root_self
+#define mx_vmar_unmap zx_vmar_unmap
+#define mx_vmo_create zx_vmo_create
+#else
 #include <magenta/process.h>
 #include <magenta/syscalls.h>
+#endif
 
 #include "src/base/macros.h"
 #include "src/base/platform/platform-posix-time.h"
@@ -162,3 +182,20 @@ bool VirtualMemory::HasLazyCommits() {
 
 }  // namespace base
 }  // namespace v8
+
+#if defined(CHROMIUM_ROLLING_MAGENTA_TO_ZIRCON)
+#undef MX_OK ZX_OK
+#undef MX_PROP_NAME ZX_PROP_NAME
+#undef MX_VM_FLAG_PERM_EXECUTE ZX_VM_FLAG_PERM_EXECUTE
+#undef MX_VM_FLAG_PERM_READ ZX_VM_FLAG_PERM_READ
+#undef MX_VM_FLAG_PERM_WRITE ZX_VM_FLAG_PERM_WRITE
+#undef mx_handle_close zx_handle_close
+#undef mx_handle_t zx_handle_t
+#undef mx_object_set_property zx_object_set_property
+#undef mx_status_t zx_status_t
+#undef mx_vmar_map zx_vmar_map
+#undef mx_vmar_protect zx_vmar_protect
+#undef mx_vmar_root_self zx_vmar_root_self
+#undef mx_vmar_unmap zx_vmar_unmap
+#undef mx_vmo_create zx_vmo_create
+#endif