Move GetDocument method from WebFrame to WebLocalFrame.

extensions/renderer/script_context.cc

Index: extensions/renderer/script_context.cc
diff --git a/extensions/renderer/script_context.cc b/extensions/renderer/script_context.cc
index 197e6c0c764c6ee96c514d876b832a2dea46894d..5e41ec4e57868419253c5c2551aca06313fde3e8 100644
--- a/extensions/renderer/script_context.cc
+++ b/extensions/renderer/script_context.cc
@@ -300,7 +300,7 @@ GURL ScriptContext::GetAccessCheckedFrameURL(
 }
 
 // static
-GURL ScriptContext::GetEffectiveDocumentURL(const blink::WebLocalFrame* frame,
+GURL ScriptContext::GetEffectiveDocumentURL(blink::WebLocalFrame* frame,
                                             const GURL& document_url,
                                             bool match_about_blank) {
   // Common scenario. If |match_about_blank| is false (as is the case in most
@@ -312,7 +312,8 @@ GURL ScriptContext::GetEffectiveDocumentURL(const blink::WebLocalFrame* frame,
   // Non-sandboxed about:blank and about:srcdoc pages inherit their security
   // origin from their parent frame/window. So, traverse the frame/window
   // hierarchy to find the closest non-about:-page and return its URL.
-  const blink::WebFrame* parent = frame;
+  blink::WebFrame* parent = frame;

[Łukasz Anforowicz, 2017/06/15 20:15:59]

The is no const-aware version of ToWebLocalFrame method, so I had to change
constness of the |parent| variable (and it cascaded into changing constness of
parameters in ScriptContext::GetEffectiveDocumentURL above and also in
extensions/renderer/script_context_set.cc and
extensions/renderer/script_context_browsertest.cc).

+  blink::WebDocument parent_document;
   do {
     if (parent->Parent())
       parent = parent->Parent();
@@ -320,12 +321,15 @@ GURL ScriptContext::GetEffectiveDocumentURL(const blink::WebLocalFrame* frame,
       parent = parent->Opener();
     else
       parent = nullptr;
-  } while (parent && !parent->GetDocument().IsNull() &&
-           GURL(parent->GetDocument().Url()).SchemeIs(url::kAboutScheme));
 
-  if (parent && !parent->GetDocument().IsNull()) {
+    parent_document = blink::WebDocument();

[dcheng, 2017/06/15 23:17:00]

Nit: no need to set parent_document here, it's already default constructed on
line 316. Maybe move the declaration down here for clarity though?

[Łukasz Anforowicz, 2017/06/16 19:39:24]

We might need to reset |parent_document| on subsequent iterations.  And moving
the declaration here won't work because this variable is used from 1) the loop
condition and 2) from the if below (on line 331).

I've tweaked the code slightly, so maybe it looks a bit nicer now.

+    if (parent && parent->IsWebLocalFrame())
+      parent_document = parent->ToWebLocalFrame()->GetDocument();
+  } while (!parent_document.IsNull() &&
+           GURL(parent_document.Url()).SchemeIs(url::kAboutScheme));
+
+  if (!parent_document.IsNull()) {
     // Only return the parent URL if the frame can access it.
-    const blink::WebDocument& parent_document = parent->GetDocument();
     if (frame->GetDocument().GetSecurityOrigin().CanAccess(
             parent_document.GetSecurityOrigin())) {
       return parent_document.Url();