Make cc::CompositorFrames movable [Part 1 of 2]

content/test/mailbox_output_surface.cc

Index: content/test/mailbox_output_surface.cc
diff --git a/content/test/mailbox_output_surface.cc b/content/test/mailbox_output_surface.cc
index 4f4dd0d03a51642f9836e588c6465d944bfa924a..7a585eb978195e18eb909522601d326cf2267976 100644
--- a/content/test/mailbox_output_surface.cc
+++ b/content/test/mailbox_output_surface.cc
@@ -218,7 +218,8 @@ void MailboxOutputSurface::ShortcutSwapAck(
   previous_frame_ack_->gl_frame_data = std::move(gl_frame_data);
 }
 
-void MailboxOutputSurface::SwapBuffers(cc::CompositorFrame* frame) {
+void MailboxOutputSurface::SwapBuffers(
+    std::unique_ptr<cc::CompositorFrame> frame) {
   // This class is here to support layout tests that are currently
   // doing a readback in the renderer instead of the browser. So they
   // are using deprecated code paths in the renderer and don't need to