Fixes tests that use internals.observeGC to work with Ignition.

third_party/WebKit/LayoutTests/resources/observeGC.js

+// Returns a GCObservation object for the object returned by the

[rmcilroy, 2016/05/13 11:21:08]

Add copyright notice.

[mythria, 2016/05/16 09:27:57]

As discussed offline. We don't need it here.

+// getObjectToObserve function. This is intended to help in observing if a GC
+// has succesfully collected the object. When using interpreter (--ignition
+// flag), dead registers are not cleared. The object that is passed to observeGC
+// might be held in a dead register, preventing GC from collecting it. To avoid

[rmcilroy, 2016/05/13 11:21:08]

The "register" terminology is to technical to understand here. Just talk about
temporary expression values remaining on the stack frame, which could keep the
object alive."

Also, add newlines between the description of how to use the function and the
description of why it's necessary.

[mythria, 2016/05/16 09:27:57]

Done.

+// this, a function that returns the object is passed as a parameter instead of
+// the object itself. Registers are released on function return.
+function observeGC(getObjectToObserve) {
+    return internals.observeGC(getObjectToObserve());
+}