Add an explicit bool conversion to scoped_refptr<T>.

base/memory/ref_counted_unittest.cc

Index: base/memory/ref_counted_unittest.cc
diff --git a/base/memory/ref_counted_unittest.cc b/base/memory/ref_counted_unittest.cc
index e8eb0fd90f6c507912299eec14a53ef015e027c2..265f31d0ac2b1a9fd3296c6cdfd7a27b277a0e8a 100644
--- a/base/memory/ref_counted_unittest.cc
+++ b/base/memory/ref_counted_unittest.cc
@@ -60,3 +60,20 @@ TEST(RefCountedUnitTest, ScopedRefPtrToSelf) {
   check->SelfDestruct();
   EXPECT_TRUE(ScopedRefPtrToSelf::was_destroyed());
 }
+
+TEST(RefCountedUnitTest, ScopedRefPtrBooleanOperations) {
+  scoped_refptr<SelfAssign> p1 = new SelfAssign;
+  scoped_refptr<SelfAssign> p2;
+  EXPECT_TRUE(p1);
+  EXPECT_FALSE(!p1);
+  EXPECT_TRUE(!p2);
+  EXPECT_FALSE(p2);
+  EXPECT_NE(p1, p2);
+  SelfAssign* raw_p = new SelfAssign;
+  p2 = raw_p;
+  EXPECT_NE(p1, p2);
+  EXPECT_EQ(raw_p, p2);
+  p2 = p1;
+  EXPECT_NE(raw_p, p2);
+  EXPECT_EQ(p1, p2);
+}