Bug 1162772, part 2 - Expose whether SEC_FORCE_INHERIT_PRINCIPAL was dropped from an nsILoadInfo. r=bz

MozReview-Commit-ID: 5Em9qXwDUIJ

netwerk/base/LoadInfo.cpp

@@ -88,6 +88,7 @@ LoadInfo::LoadInfo(nsIPrincipal* aLoadingPrincipal,
   // if the load is sandboxed, we can not also inherit the principal
   if (mSecurityFlags & nsILoadInfo::SEC_SANDBOXED) {
     mSecurityFlags ^= nsILoadInfo::SEC_FORCE_INHERIT_PRINCIPAL;
+    mSecurityFlags |= nsILoadInfo::SEC_FORCE_INHERIT_PRINCIPAL_WAS_DROPPED;
   }
 
   if (aLoadingContext) {
@@ -194,6 +195,7 @@ LoadInfo::LoadInfo(nsPIDOMWindowOuter* aOuterWindow,
   // if the load is sandboxed, we can not also inherit the principal
   if (mSecurityFlags & nsILoadInfo::SEC_SANDBOXED) {
     mSecurityFlags ^= nsILoadInfo::SEC_FORCE_INHERIT_PRINCIPAL;
+    mSecurityFlags |= nsILoadInfo::SEC_FORCE_INHERIT_PRINCIPAL_WAS_DROPPED;
   }
 
   // NB: Ignore the current inner window since we're navigating away from it.

netwerk/base/nsILoadInfo.idl

@@ -118,7 +118,10 @@ interface nsILoadInfo : nsISupports
    * is loading the URI "http://b.com/whatever", GetChannelResultPrincipal
    * will return a principal from "http://a.com/".
    *
-   * This flag can not be used together with SEC_SANDBOXED.
+   * This flag can not be used together with SEC_SANDBOXED.  If both are passed
+   * to the LoadInfo constructor then this flag will be dropped.  If you need
+   * to know whether this flag would have been present but was dropped due to
+   * sandboxing, check for the SEC_FORCE_INHERIT_PRINCIPAL_WAS_DROPPED flag.
    */
   const unsigned long SEC_FORCE_INHERIT_PRINCIPAL = (1<<7);
 
@@ -166,6 +169,14 @@ interface nsILoadInfo : nsISupports
    */
   const unsigned long SEC_FORCE_PRIVATE_BROWSING = (1<<12);
 
+  /**
+   * The SEC_FORCE_INHERIT_PRINCIPAL flag may be dropped when a load info
+   * object is created.  Specifically, it will be dropped if the SEC_SANDBOXED
+   * flag is also present.  This flag is set if SEC_FORCE_INHERIT_PRINCIPAL was
+   * dropped.
+   */
+  const unsigned long SEC_FORCE_INHERIT_PRINCIPAL_WAS_DROPPED = (1<<13);
+
   /**
    * The loadingPrincipal is the principal that is responsible for the load.
    * It is *NOT* the principal tied to the resource/URI that this