Rendering text to a canvas in a frame-less document.

third_party/WebKit/Source/core/dom/Element.cpp

Index: third_party/WebKit/Source/core/dom/Element.cpp
diff --git a/third_party/WebKit/Source/core/dom/Element.cpp b/third_party/WebKit/Source/core/dom/Element.cpp
index 9413e11c80503879e1f35e758ba316ad110329ec..71a4a4b1f4c73a1bc7050fd7ad583f651ab42692 100644
--- a/third_party/WebKit/Source/core/dom/Element.cpp
+++ b/third_party/WebKit/Source/core/dom/Element.cpp
@@ -2887,7 +2887,7 @@ const ComputedStyle* Element::ensureComputedStyle(PseudoId pseudoElementSpecifie
     if (PseudoElement* element = pseudoElement(pseudoElementSpecifier))
         return element->ensureComputedStyle();
 
-    if (!inActiveDocument()) {
+    if (!inActiveDocument() && document().frame()) {

[esprehn, 2016/09/26 22:23:37]

This is not correct, it means we don't return null here if your document had no
frame. Which makes us call ensureStyleResolver below on an frameless document
which will crash.

inActiveDocument() is guarding the code below. I'm also curious why you'd want
to run the style code for elements not in the document but inside a frameless
document? It seems strange we'd special case on frame here, in general this code
shouldn't care about that, it's about being in an active document (capable of
computing style) or not.

         // FIXME: Try to do better than this. Ensure that styleForElement() works for elements that are not in the
         // document tree and figure out when to destroy the computed style for such elements.
         return nullptr;