gfx: Fix sending an invalid GpuMemoryBufferHandle over mojo.

ui/gfx/mojo/buffer_types_traits.cc

Index: ui/gfx/mojo/buffer_types_traits.cc
diff --git a/ui/gfx/mojo/buffer_types_traits.cc b/ui/gfx/mojo/buffer_types_traits.cc
index 71cef1b8fb133e8c462c72f01b4f1b084cf3d804..122d844079e0c056813829de1698a055219e8cec 100644
--- a/ui/gfx/mojo/buffer_types_traits.cc
+++ b/ui/gfx/mojo/buffer_types_traits.cc
@@ -72,6 +72,8 @@ mojo::ScopedHandle StructTraits<gfx::mojom::GpuMemoryBufferHandleDataView,
   DCHECK(handle.handle.auto_close || handle.handle.fd == -1);
   platform_file = handle.handle.fd;
 #endif
+  if (platform_file == base::kInvalidPlatformFile)
+    return mojo::ScopedHandle();
   return mojo::WrapPlatformFile(platform_file);
 }
 
@@ -94,20 +96,25 @@ bool StructTraits<gfx::mojom::GpuMemoryBufferHandleDataView,
   if (!data.ReadType(&out->type) || !data.ReadId(&out->id))
     return false;
 
-  base::PlatformFile platform_file;
-  MojoResult unwrap_result = mojo::UnwrapPlatformFile(
-      data.TakeSharedMemoryHandle(), &platform_file);
-  if (unwrap_result != MOJO_RESULT_OK)
-    return false;
+  mojo::ScopedHandle handle = data.TakeSharedMemoryHandle();
+  if (handle.is_valid()) {
+    base::PlatformFile platform_file;
+    MojoResult unwrap_result = mojo::UnwrapPlatformFile(
+        std::move(handle), &platform_file);
+    if (unwrap_result != MOJO_RESULT_OK)
+      return false;
 #if defined(OS_WIN)
-  out->handle =
-      base::SharedMemoryHandle(platform_file, base::GetCurrentProcId());
+    out->handle =
+        base::SharedMemoryHandle(platform_file, base::GetCurrentProcId());
 #elif defined(OS_MACOSX) || defined(OS_IOS)
-  // TODO: Add support for mach_port on mac.
-  out->handle = base::SharedMemoryHandle();
+    // TODO: Add support for mach_port on mac.
+    out->handle = base::SharedMemoryHandle();
 #else
-  out->handle = base::SharedMemoryHandle(platform_file, true);
+    out->handle = base::SharedMemoryHandle(platform_file, true);
 #endif
+  } else {
+    out->handle = base::SharedMemoryHandle();
+  }
 
   out->offset = data.offset();
   out->stride = data.stride();