LibGfx: Short-circuit ShareableBitmap construction in IPC decoder

When decoding a ShareableBitmap that came over IPC, it's safe to assume
that it's backed by an anonymous file (since we just decoded it.)

2 files changed, 11 insertions, 1 deletions

diff --git a/Userland/Libraries/LibGfx/ShareableBitmap.cpp b/Userland/Libraries/LibGfx/ShareableBitmap.cpp
index 2ab5ece797..1edf498096 100644
--- a/Userland/Libraries/LibGfx/ShareableBitmap.cpp
+++ b/Userland/Libraries/LibGfx/ShareableBitmap.cpp
@@ -38,6 +38,11 @@ ShareableBitmap::ShareableBitmap(const Bitmap& bitmap)
 {
 }
 
+ShareableBitmap::ShareableBitmap(NonnullRefPtr<Bitmap> bitmap, Tag)
+    : m_bitmap(move(bitmap))
+{
+}
+
 }
 
 namespace IPC {
@@ -70,7 +75,9 @@ bool decode(Decoder& decoder, Gfx::ShareableBitmap& shareable_bitmap)
         return false;
 
     auto bitmap = Gfx::Bitmap::create_with_anon_fd(Gfx::BitmapFormat::RGBA32, anon_file.take_fd(), size, Gfx::Bitmap::ShouldCloseAnonymousFile::Yes);
-    shareable_bitmap = bitmap->to_shareable_bitmap();
+    if (!bitmap)
+        return false;
+    shareable_bitmap = Gfx::ShareableBitmap { bitmap.release_nonnull(), Gfx::ShareableBitmap::ConstructWithKnownGoodBitmap };
     return true;
 }
 
diff --git a/Userland/Libraries/LibGfx/ShareableBitmap.h b/Userland/Libraries/LibGfx/ShareableBitmap.h
index 06ef331c54..d6eecd3cbb 100644
--- a/Userland/Libraries/LibGfx/ShareableBitmap.h
+++ b/Userland/Libraries/LibGfx/ShareableBitmap.h
@@ -37,6 +37,9 @@ public:
     ShareableBitmap() { }
     explicit ShareableBitmap(const Gfx::Bitmap&);
 
+    enum Tag { ConstructWithKnownGoodBitmap };
+    ShareableBitmap(NonnullRefPtr<Gfx::Bitmap>, Tag);
+
     bool is_valid() const { return m_bitmap; }
 
     const Bitmap* bitmap() const { return m_bitmap; }