Add MessageLoopForUI to the ubsan vptr blacklist.

tools/ubsan/vptr_blacklist.txt

 #############################################################################
 # UBSan vptr blacklist.
 # Function and type based blacklisting use a mangled name, and it is especially
 # tricky to represent C++ types. For now, any possible changes by name manglings
 # are simply represented as wildcard expressions of regexp, and thus it might be
 # over-blacklisted.
 
 #############################################################################
 # Identical layouts.
 # If base and derived classes have identifical memory layouts (i.e., the same
 # object size) and both have no virtual functions, we blacklist them as there
 # would be not much security implications.
 
 fun:*LifecycleNotifier*addObserver*
 fun:*LifecycleNotifier*removeObserver*
 fun:*toWebInputElement*
 type:*base*MessageLoopForIO*
+type:*base*MessageLoopForUI*
 type:*BlockRefType*
 type:*SkAutoTUnref*
 type:*WDResult*
 type:*ExecutionContext*
 type:*WebInputElement*
 type:*WebFormControlElement*
 
 # Avoid identical layout cases for 86 different classes in InspectorTypeBuilder,
 # all of which are guarded using COMPILER_ASSERT on the object size. Two more
 # types are also blacklisted due to the template class (JSONArray <-> Array<T>).
@@ skipping 13 matching lines @@
 
 # RenderViewObserverTracker<T>::RenderViewObserverTracker()
 fun:*content*RenderViewObserverTracker*RenderView*
 
 #############################################################################
 # Base class's destructor accesses a derived class.
 
 fun:*DatabaseContext*contextDestroyed*
 
 # FIXME: Cannot handle template function LifecycleObserver<>::setContext,
-# so exclude source file for now. 
+# so exclude source file for now.
 src:*LifecycleObserver.h*
 
 #############################################################################
 # static_cast into itself in the constructor.
 
 fun:*RefCountedGarbageCollected*makeKeepAlive*
 fun:*ThreadSafeRefCountedGarbageCollected*makeKeepAlive*
 
 #############################################################################
 # Accessing data in destructors where the class has virtual inheritances.
@@ skipping 68 matching lines @@
 #############################################################################
 # UBsan goes into an infinite recursion when __dynamic_cast instrumented with
 # "vptr". See crbug.com/609786.
 
 src:*/third_party/libc\+\+abi/trunk/src/private_typeinfo.cpp
 
 #############################################################################
 # invalid downcasts for IPC messages
 # https://crbug.com/520760
 src:*nacl_message_scanner.cc