Bug 1251311. JS::DescribeScriptedCaller can't throw JS exceptions. Adjust some callers accordingly. r=khuey

caps/nsScriptSecurityManager.cpp

@@ -495,6 +495,8 @@ nsScriptSecurityManager::ContentSecurityPolicyPermitsJSAction(JSContext *cx)
             if (const char *file = scriptFilename.get()) {
                 CopyUTF8toUTF16(nsDependentCString(file), fileName);
             }
+        } else {
+            MOZ_ASSERT(!JS_IsExceptionPending(cx));
         }
         csp->LogViolationDetails(nsIContentSecurityPolicy::VIOLATION_TYPE_EVAL,
                                  fileName,

dom/workers/RuntimeService.cpp

@@ -633,7 +633,7 @@ ContentSecurityPolicyAllows(JSContext* aCx)
     if (JS::DescribeScriptedCaller(aCx, &file, &lineNum) && file.get()) {
       fileName = NS_ConvertUTF8toUTF16(file.get());
     } else {
-      JS_ReportPendingException(aCx);
+      MOZ_ASSERT(!JS_IsExceptionPending(aCx));
     }
 
     RefPtr<LogViolationDetailsRunnable> runnable =