ActiveSupport::Notifications::Instrumenter#instrument should yield

its payload the same way that ActiveSupport::Notifications does.
Fix spelling in test name.

activesupport/CHANGELOG.md

 ## Rails 4.0.0 (unreleased) ##
 
+*   `ActiveSupport::Notifications::Instrumenter#instrument` should yield
+    its payload.
+
+    *stopdropandrew*
+
 *   Fix deletion of empty directories in ActiveSupport::Cache::FileStore.
-    
+
     *Charles Jones*
 
 ## Rails 4.0.0.beta1 (February 25, 2013) ##

activesupport/lib/active_support/notifications/instrumenter.rb

@@ -17,7 +17,7 @@ def initialize(notifier)
       def instrument(name, payload={})
         start name, payload
         begin
-          yield
+          yield payload
         rescue Exception => e
           payload[:exception] = [e.class.name, e.message]
           raise e

activesupport/test/notifications/instrumenter_test.rb

@@ -34,6 +34,14 @@ def test_instrument
         assert called
       end
 
+      def test_instrument_yields_the_payload_for_further_modification
+        assert_equal 2, instrumenter.instrument("awesome") { |p| p[:result] = 1 + 1 }
+        assert_equal 1, notifier.finishes.size
+        name, _, payload = notifier.finishes.first
+        assert_equal "awesome", name
+        assert_equal Hash[:result => 2], payload
+      end
+
       def test_start
         instrumenter.start("foo", payload)
         assert_equal [["foo", instrumenter.id, payload]], notifier.starts

activesupport/test/notifications_test.rb

@@ -157,7 +157,7 @@ def test_instrument_returns_block_result
       assert_equal 2, instrument(:awesome) { 1 + 1 }
     end
 
-    def test_instrument_yields_the_paylod_for_further_modification
+    def test_instrument_yields_the_payload_for_further_modification
       assert_equal 2, instrument(:awesome) { |p| p[:result] = 1 + 1 }
       assert_equal 1, @events.size
       assert_equal :awesome, @events.first.name