Cleaning up base::Value assignment.

base/values.cc

Index: base/values.cc
diff --git a/base/values.cc b/base/values.cc
index 5cc0d693bdd11c12e60f14f8921bec3cd303e4da..477d38291177b1537ae793cfbf3a1b287055455e 100644
--- a/base/values.cc
+++ b/base/values.cc
@@ -173,26 +173,24 @@ Value::Value(std::vector<char>&& in_blob) : type_(Type::BINARY) {
 }
 
 Value& Value::operator=(const Value& that) {
-  if (this != &that) {
-    if (type_ == that.type_) {
-      InternalCopyAssignFromSameType(that);
-    } else {
-      InternalCleanup();
-      InternalCopyConstructFrom(that);
-    }
+  if (type_ == that.type_) {
+    InternalCopyAssignFromSameType(that);
+  } else {
+    // this is not a self assignment because the type_ doesn't match.
+    InternalCleanup();
+    InternalCopyConstructFrom(that);
   }
 
   return *this;
 }
 
 Value& Value::operator=(Value&& that) {
-  if (this != &that) {
-    if (type_ == that.type_) {
-      InternalMoveAssignFromSameType(std::move(that));
-    } else {
-      InternalCleanup();
-      InternalMoveConstructFrom(std::move(that));
-    }
+  if (type_ == that.type_) {
+    DCHECK(this != &that) << " attempt to self move assign.";
+    InternalMoveAssignFromSameType(std::move(that));

[dcheng, 2017/03/10 18:40:15]

We should just remove the branch entirely if we're DCHECKing.

[dyaroshev, 2017/03/10 18:54:57]

Done.
std::variant (http://en.cppreference.com/w/cpp/utility/variant/operator%3D) (on
which this is based) would check for matching types - but I've double checked -
there does not seem to be a gain.

+  } else {
+    InternalCleanup();
+    InternalMoveConstructFrom(std::move(that));
   }
 
   return *this;