CopyOutputResult must have a working release callback when received over mojo

cc/ipc/copy_output_result_struct_traits.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/ipc/copy_output_result_struct_traits.h"
 
+void Release(cc::mojom::TextureMailboxReleaserPtr ptr,
+             const gpu::SyncToken& sync_token,
+             bool is_lost) {
+  ptr->Release(sync_token, is_lost);
+}
+
 namespace mojo {
 
 // static
+const SkBitmap& StructTraits<cc::mojom::CopyOutputResultDataView,
+                             std::unique_ptr<cc::CopyOutputResult>>::
+    bitmap(const std::unique_ptr<cc::CopyOutputResult>& result) {
+  static SkBitmap* null_bitmap = new SkBitmap();
+  if (!result->bitmap_)
+    return *null_bitmap;
+  return *result->bitmap_;
+}
+
+// static
+cc::mojom::TextureMailboxReleaserPtr
+StructTraits<cc::mojom::CopyOutputResultDataView,
+             std::unique_ptr<cc::CopyOutputResult>>::
+    releaser(const std::unique_ptr<cc::CopyOutputResult>& result) {
+  if (result->release_callback_) {
+    DCHECK(result->ptr_provider_);
+    return result->ptr_provider_->GetTextureMailboxReleaser(
+        std::move(result->release_callback_));
+  } else {
+    return cc::mojom::TextureMailboxReleaserPtr();
+  }
+}
+
+// static
 bool StructTraits<cc::mojom::CopyOutputResultDataView,
                   std::unique_ptr<cc::CopyOutputResult>>::
     Read(cc::mojom::CopyOutputResultDataView data,
          std::unique_ptr<cc::CopyOutputResult>* out_p) {
   auto result = cc::CopyOutputResult::CreateEmptyResult();
 
   if (!data.ReadSize(&result->size_))
     return false;
 
   result->bitmap_ = base::MakeUnique<SkBitmap>();
   if (!data.ReadBitmap(result->bitmap_.get()))
     return false;
 
   if (!data.ReadTextureMailbox(&result->texture_mailbox_))
     return false;
 
+  auto releaser = data.TakeReleaser<cc::mojom::TextureMailboxReleaserPtr>();
+  if (releaser) {
+    result->release_callback_ = cc::SingleReleaseCallback::Create(
+        base::Bind(Release, base::Passed(&releaser)));
+  }
+
   *out_p = std::move(result);
 
   return true;
 }
 
-// static
-const SkBitmap& StructTraits<cc::mojom::CopyOutputResultDataView,
-                             std::unique_ptr<cc::CopyOutputResult>>::
-    bitmap(const std::unique_ptr<cc::CopyOutputResult>& result) {
-  static SkBitmap* null_bitmap = new SkBitmap();
-  if (!result->bitmap_)
-    return *null_bitmap;
-  return *result->bitmap_;
-}
-
 }  // namespace mojo