Remove uses of deprecated toWebCoreStringWithUndefinedOrNullCheck(v8::Handle<v8::Value>)

Remove uses of deprecated toWebCoreStringWithUndefinedOrNullCheck(v8::Handle<v8::Value>) and
use V8TRYCATCH_FOR_V8STRINGRESOURCE*() macros instead so that we return early if an exception
is thrown by v8::String::ToString().

R=haraken

Review URL: https://codereview.chromium.org/110663003

git-svn-id: svn://svn.chromium.org/blink/trunk@163492 bbb929c8-8fbe-4397-9dbb-9b2b20218538