CSP: Permit exempting schemes only for certain policy areas.

public/web/WebSecurityPolicy.h

Index: public/web/WebSecurityPolicy.h
diff --git a/public/web/WebSecurityPolicy.h b/public/web/WebSecurityPolicy.h
index dc834c1d96f2b75cfc9124fd32e1f3a5b1a506c5..d7acab0caabf41e9e1006165e4bf14e6e25d3d25 100644
--- a/public/web/WebSecurityPolicy.h
+++ b/public/web/WebSecurityPolicy.h
@@ -67,6 +67,18 @@ public:
     // Registers a URL scheme whose resources can be loaded regardless of a page's Content Security Policy.
     BLINK_EXPORT static void registerURLSchemeAsBypassingContentSecurityPolicy(const WebString&);
 
+    // Registers a URL scheme for which some kinds of resources bypass Content Security Policy.
+    // This enum should be kept in sync with Source/platform/weborigin/SchemeRegistry.h.
+    // Enforced in AssertMatchingEnums.cpp.
+    enum PolicyAreas : uint32_t {
+        PolicyAreaNone = 0,
+        PolicyAreaImage = 1 << 0,
+        PolicyAreaStyle = 1 << 1,
+        // Add more policy areas as needed by clients.
+        PolicyAreaAll = ~static_cast<uint32_t>(0),
+    };
+    BLINK_EXPORT static void registerURLSchemeAsBypassingContentSecurityPolicy(const WebString& scheme, PolicyAreas);
+
     // Registers a URL scheme as strictly empty documents, allowing them to
     // commit synchronously.
     BLINK_EXPORT static void registerURLSchemeAsEmptyDocument(const WebString&);