Convert //ppapi to use std::unique_ptr

BUG=554298
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Review URL: https://codereview.chromium.org/1864293002

Cr-Commit-Position: refs/heads/master@{#385591}
diff --git a/ppapi/proxy/ppb_graphics_3d_proxy.h b/ppapi/proxy/ppb_graphics_3d_proxy.h
index e2b4dda..fab0122 100644
--- a/ppapi/proxy/ppb_graphics_3d_proxy.h
+++ b/ppapi/proxy/ppb_graphics_3d_proxy.h
@@ -62,7 +62,7 @@
   gpu::GpuControl* GetGpuControl() override;
   int32_t DoSwapBuffers(const gpu::SyncToken& sync_token) override;
 
-  scoped_ptr<PpapiCommandBufferProxy> command_buffer_;
+  std::unique_ptr<PpapiCommandBufferProxy> command_buffer_;
 
   DISALLOW_COPY_AND_ASSIGN(Graphics3D);
 };