Revert "Change call-sites now that SkCanvas is not ref-counted"

cc/output/software_renderer.cc

Index: cc/output/software_renderer.cc
diff --git a/cc/output/software_renderer.cc b/cc/output/software_renderer.cc
index d14526eb5f2d9852fa498bbe7f3ccde26f5f436f..4a4d89097ff30d9a953ab435cedc018e09e21fb5 100644
--- a/cc/output/software_renderer.cc
+++ b/cc/output/software_renderer.cc
@@ -128,7 +128,7 @@ bool SoftwareRenderer::BindFramebufferToTexture(
       base::MakeUnique<ResourceProvider::ScopedWriteLockSoftware>(
           resource_provider_, texture->id());
   current_framebuffer_canvas_ =
-      base::MakeUnique<SkCanvas>(current_framebuffer_lock_->sk_bitmap());
+      sk_make_sp<SkCanvas>(current_framebuffer_lock_->sk_bitmap());
   current_canvas_ = current_framebuffer_canvas_.get();
   return true;
 }