Part 1.1: Is policy list subsumed under subsuming policy?

third_party/WebKit/Source/core/frame/csp/CSPSource.h

Index: third_party/WebKit/Source/core/frame/csp/CSPSource.h
diff --git a/third_party/WebKit/Source/core/frame/csp/CSPSource.h b/third_party/WebKit/Source/core/frame/csp/CSPSource.h
index d7295244feed27c8b4ac7bf5a0e9e0c5100e549c..796a8f75756949df7ec60791d037fe4d16669d05 100644
--- a/third_party/WebKit/Source/core/frame/csp/CSPSource.h
+++ b/third_party/WebKit/Source/core/frame/csp/CSPSource.h
@@ -31,6 +31,9 @@ class CORE_EXPORT CSPSource : public GarbageCollectedFinalized<CSPSource> {
   bool matches(const KURL&,
                ResourceRequest::RedirectStatus =
                    ResourceRequest::RedirectStatus::NoRedirect) const;
+  bool isSubsumed(CSPSource*);

[Mike West, 2016/10/26 11:40:30]

Nit: Please add a comment here, and probably point off to
https://w3c.github.io/webappsec-csp/embedded/#subsume-policy. In particular,
does `true` mean that `this` is subsumed _by_ `b`, or that `this` _subsumes_
`b`? Perhaps changing the name to `subsumes()` or `isSubsumedBy()` could
clarify?

+  // Find the normalized CSPSource of the two.

[Mike West, 2016/10/26 11:40:30]

1. What does "normalize" mean?
2. It would be great to document the algorithm in the spec, and point off to it
as explanation.

+  CSPSource* getCommon(CSPSource*);
 
   DECLARE_TRACE();
 
@@ -41,6 +44,13 @@ class CORE_EXPORT CSPSource : public GarbageCollectedFinalized<CSPSource> {
   bool portMatches(const KURL&) const;
   bool isSchemeOnly() const;
 
+  bool schemeMatches(const String&) const;
+  bool hostMatches(const String&) const;
+  bool pathMatches(const String&) const;
+  bool portMatches(int, const String&) const;

[Mike West, 2016/10/26 11:40:30]

Would you mind pulling this refactoring out into a separate patch that we can
land today while we discuss the rest?

+
+  bool isSimilar(CSPSource* other);

[Mike West, 2016/10/26 11:40:30]

It's probably worth adding unit tests for this piece, and describing what
"similar" means.

+
   Member<ContentSecurityPolicy> m_policy;
   String m_scheme;
   String m_host;