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;
+  }
+
  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);
 };