Queue latency info swap promises in a separate already-active queue.

cc/output/swap_promise.h

Index: cc/output/swap_promise.h
diff --git a/cc/output/swap_promise.h b/cc/output/swap_promise.h
index cf0b88de9ebc5817a4121a79e27b436ebea03086..ca6cd2026c4462d0d7fb6ab80dfaface9a45f182 100644
--- a/cc/output/swap_promise.h
+++ b/cc/output/swap_promise.h
@@ -61,6 +61,22 @@ class CC_EXPORT SwapPromise {
   // swap promise. This can be used for registering additional flow steps to
   // visualize the object's path through the system.
   virtual int64 TraceId() const = 0;
+
+  static std::string DidNotSwapReasonToString(DidNotSwapReason reason) {

[Sami, 2015/08/18 11:19:18]

Is this used anywhere?

nit: this could just be a const char*

[Tobias Sargeant, 2015/08/18 13:39:52]

It isn't. It was useful during debugging the unittest, and I figured it was
useful to keep around. Upon reflection, I've removed it.

+    switch (reason) {
+      case SWAP_FAILS:
+        return "SWAP_FAILS";
+      case COMMIT_FAILS:
+        return "COMMIT_FAILS";
+      case COMMIT_NO_UPDATE:
+        return "COMMIT_NO_UPDATE";
+      case ACTIVATION_FAILS:
+        return "ACTIVATION_FAILS";
+      default:
+        NOTREACHED();
+        return "";
+    }
+  }
 };
 
 }  // namespace cc