ASSERTION FAILED: m_contents->isCacheable()
../../third_party/WebKit/Source/core/css/CSSStyleSheet.cpp(149) : void blink::CSSStyleSheet::willMutateRules()
1   0x1072dc95f blink::CSSStyleSheet::setText(WTF::String const&)
2   0x1075d5f82 blink::InspectorStyleSheet::setText(WTF::String const&, blink::ExceptionState&)
3   0x107579b03 blink::InspectorCSSAgent::SetStyleSheetTextAction::perform(blink::ExceptionState&)
4   0x1075ae619 blink::InspectorHistory::perform(blink::InspectorHistory::Action*, blink::ExceptionState&)
5   0x107570139 blink::InspectorCSSAgent::setStyleSheetText(blink::protocol::String16*, WTF::String const&, WTF::String const&, blink::protocol::Maybe<WTF::String>*)
6   0x10602d36e blink::protocol::DispatcherImpl::CSS_setStyleSheetText(int, int, WTF::PassOwnPtr<blink::protocol::DictionaryValue>, blink::protocol::ErrorSupport*)
7   0x106047a9c blink::protocol::DispatcherImpl::dispatch(int, blink::protocol::String16 const&)
8   0x1075d123a blink::InspectorSession::dispatchProtocolMessage(WTF::String const&)
9   0x10690e07b blink::WebDevToolsAgentImpl::dispatchOnInspectorBackend(int, blink::WebString const&)
10  0x1095337f4 content::DevToolsAgent::OnDispatchOnInspectorBackend(int, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)