SetPreviousFrameSurface should copy latency info to the new surface

content/browser/renderer_host/delegated_frame_host.cc

Index: content/browser/renderer_host/delegated_frame_host.cc
diff --git a/content/browser/renderer_host/delegated_frame_host.cc b/content/browser/renderer_host/delegated_frame_host.cc
index ffd64e3ec8a2824500e57437ad939966c5c3e87a..a107d3ebea40b4736556d3ec3cb62a4c5383e47f 100644
--- a/content/browser/renderer_host/delegated_frame_host.cc
+++ b/content/browser/renderer_host/delegated_frame_host.cc
@@ -457,18 +457,10 @@ void DelegatedFrameHost::SwapDelegatedFrame(uint32_t compositor_frame_sink_id,
       allocated_new_local_surface_id = true;
     }
 
-    gfx::Size desired_size = client_->DelegatedFrameHostDesiredSizeInDIP();
-    if (desired_size != frame_size_in_dip && !desired_size.IsEmpty()) {
-      skipped_latency_info_list_.insert(skipped_latency_info_list_.end(),
-                                        frame.metadata.latency_info.begin(),
-                                        frame.metadata.latency_info.end());
-      frame.metadata.latency_info.clear();

[tdresser, 2017/02/28 20:25:45]

I have context on LatencyInfo, but not much context on this part of the code.

The CL description makes it sound like this is just a refactor, without any
behavior change, but this looks like it's changing behavior.

Is it? If we are changing behavior, the CL description should make it clear, and
we should have a test.

-    } else {
-      frame.metadata.latency_info.insert(frame.metadata.latency_info.end(),
-                                         skipped_latency_info_list_.begin(),
-                                         skipped_latency_info_list_.end());
-      skipped_latency_info_list_.clear();
-    }
+    frame.metadata.latency_info.insert(frame.metadata.latency_info.end(),
+                                       skipped_latency_info_list_.begin(),
+                                       skipped_latency_info_list_.end());
+    skipped_latency_info_list_.clear();
 
     support_->SubmitCompositorFrame(local_surface_id_, std::move(frame));