Added utility base::BindLambda to allow passing lambdas as base::Callback<>

base/bind_unittest.cc

Index: base/bind_unittest.cc
diff --git a/base/bind_unittest.cc b/base/bind_unittest.cc
index a30b7756704658a599a84e3df88e80166e731ce7..2f3891bfd95b954ec35bacea4b2812d2aed18e6f 100644
--- a/base/bind_unittest.cc
+++ b/base/bind_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "base/bind.h"
 
+#include "base/bind_lambda.h"
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ -786,6 +787,27 @@ TEST_F(BindTest, ArgumentCopies) {
   EXPECT_EQ(0, assigns);
 }
 
+TEST_F(BindTest, Lambdas) {
+  static const int kValueToSet = 55;
+  int value_set_from_lambda = 0;
+
+  Callback<void(int)> callback =
+      BindLambda([&](int new_val) { value_set_from_lambda = new_val; });
+  callback.Run(kValueToSet);
+  EXPECT_EQ(kValueToSet, value_set_from_lambda);
+}
+
+TEST_F(BindTest, LambdasNestedInBind) {
+  static const int kValueToSet = 55;
+  int value_set_from_lambda = 0;
+
+  Callback<void()> callback =
+      Bind(BindLambda([&](int new_val) { value_set_from_lambda = new_val; }),
+           kValueToSet);
+  callback.Run();
+  EXPECT_EQ(kValueToSet, value_set_from_lambda);
+}
+
 // Callback construction and assignment tests.
 //   - Construction from an InvokerStorageHolder should not cause ref/deref.
 //   - Assignment from other callback should only cause one ref