Returning early when setting a frame name to the same name.

third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp

Index: third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
diff --git a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
index 130fa525436b6c9a99074fab4f406eab4484d746..20a01b9f6b24d98edfe157a16ae76c19f7f7615c 100644
--- a/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalDOMWindow.cpp
@@ -1056,6 +1056,9 @@ void LocalDOMWindow::setName(const AtomicString& name)
     if (!isCurrentlyDisplayedInFrame())
         return;
 
+    if (name == frame()->tree().name())
+        return;

[Łukasz Anforowicz, 2016/06/10 00:06:57]

Alex rightfully suggested that we should also short-circuit here (to avoid
unnecessary IPC to the browser).

Note that even with the early return above, we still need to tweak
FrameTree::setName, because it has more callers than just
LocalDOMWindow::setName.

+
     frame()->tree().setName(name);
     ASSERT(frame()->loader().client());
     frame()->loader().client()->didChangeName(name, frame()->tree().uniqueName());