Limit PDF helper extension to print preview only

chrome/browser/resources/pdf/browser_api.js

Index: chrome/browser/resources/pdf/browser_api.js
diff --git a/chrome/browser/resources/pdf/browser_api.js b/chrome/browser/resources/pdf/browser_api.js
index 90033b84085322370cabe103d2970fd738817a56..10a4ad370296f56697378b4390354080add48e2c 100644
--- a/chrome/browser/resources/pdf/browser_api.js
+++ b/chrome/browser/resources/pdf/browser_api.js
@@ -206,7 +206,7 @@ function createBrowserApiForStandaloneExtension() {
  *     current environment.
  */
 function createBrowserApi() {
-  if (window.location.search)
+  if (location.search && location.ancestorOrigins[0] === 'chrome://print')

[raymes, 2016/10/11 06:24:44]

Do we need the window.location.search check too?

[robwu, 2016/10/11 21:05:38]

Yes. When loaded inside the plugin location.ancestorOrigins.length === 0, which
is indistinguishable from being loaded in the top-level frame.

     return createBrowserApiForStandaloneExtension();
 
   return createBrowserApiForMimeHandlerView();