base: Add serialization support to Pixels and FrameBuffer

Serialize pixels as unsigned 32 bit integers by adding the required
to_number() and stream operators. This is used by the FrameBuffer,
which now implements the Serializable interface. Users of frame
buffers are expected to serialize it into its own section by calling
serializeSection().

src/base/framebuffer.cc

@@ -122,6 +122,23 @@ FrameBuffer::~FrameBuffer()
 {
 }
 
+
+void
+FrameBuffer::serialize(CheckpointOut &cp) const
+{
+    SERIALIZE_SCALAR(_width);
+    SERIALIZE_SCALAR(_height);
+    SERIALIZE_CONTAINER(pixels);
+}
+
+void
+FrameBuffer::unserialize(CheckpointIn &cp)
+{
+    UNSERIALIZE_SCALAR(_width);
+    UNSERIALIZE_SCALAR(_height);
+    UNSERIALIZE_CONTAINER(pixels);
+}
+
 void
 FrameBuffer::resize(unsigned width, unsigned height)
 {