Inject renderer recieve message time into resource notifications.

content/common/resource_dispatcher.h

Index: content/common/resource_dispatcher.h
diff --git a/content/common/resource_dispatcher.h b/content/common/resource_dispatcher.h
index 141e89c188c4b102c01f4a61bdfbbdc6dd43c288..91e8942f9a0bd6a95fdbe47b05db975fb93d8f3b 100644
--- a/content/common/resource_dispatcher.h
+++ b/content/common/resource_dispatcher.h
@@ -71,6 +71,11 @@ class CONTENT_EXPORT ResourceDispatcher : public IPC::Listener {
     delegate_ = delegate;
   }
 
+  // Remembers IO thread timestamp for next resource message.
+  void set_io_timestamp(base::TimeTicks io_timestamp) {
+    io_timestamp_ = io_timestamp;

[James Simonsen, 2013/04/26 23:02:28]

What happens if there are many resource messages queued? Admittedly it's better
than what we have today, but it's still not exactly what we want. Could we add a
field to the messages themselves instead?

[eustas, 2013/04/29 08:59:03]

I've got exactly the same idea first (see Patch Set 1).
I've added fields to messages and tampered them in filter.
But this looks too hacky, because (conceptually) filters should not change
messages (they get const IPC::Message).

If I'm not mistaken, setting timestamps and receiving messages tasks will be
interleaved, so each message will correspond to its own timestamp.

+  }
+
  private:
   friend class ResourceDispatcherTest;
 
@@ -180,6 +185,8 @@ class CONTENT_EXPORT ResourceDispatcher : public IPC::Listener {
 
   ResourceDispatcherDelegate* delegate_;
 
+  base::TimeTicks io_timestamp_;
+
   DISALLOW_COPY_AND_ASSIGN(ResourceDispatcher);
 };