Split content script injections into multiple tasks

chrome/test/data/extensions/api_test/content_scripts/about_blank_iframes/test.js

Index: chrome/test/data/extensions/api_test/content_scripts/about_blank_iframes/test.js
diff --git a/chrome/test/data/extensions/api_test/content_scripts/about_blank_iframes/test.js b/chrome/test/data/extensions/api_test/content_scripts/about_blank_iframes/test.js
index 5d08ce0a68dd5d10f773dea4f73eff7770fbdd86..099b0b538d48e0c55a46310b3bbb0663ecda9790 100644
--- a/chrome/test/data/extensions/api_test/content_scripts/about_blank_iframes/test.js
+++ b/chrome/test/data/extensions/api_test/content_scripts/about_blank_iframes/test.js
@@ -43,19 +43,12 @@ chrome.test.getConfig(function(config) {
       chrome.tabs.create({ url: test_url });
     },
     function testDocumentStartRunsInSameWorldAsDocumentEndOfJavaScriptUrl() {
-      var hasReceivedFirstMessage = false;
       onRequest.addListener(function listener(request) {
-        if (!hasReceivedFirstMessage) {

[Devlin, 2017/02/13 23:13:09]

Why this change?

[Kunihiko Sakamoto, 2017/02/14 09:07:54]

For an iframe with src= javascript: URL, blink opens a frame with about:blank
URL and then execute the JS and replaces the document with the execution result.
 Currently, document_end scripts are injected twice in this process, once for
about:blank and once for the replaced document.

My change delays document_end injections. As a result, the replacement happens
first, so document_end scripts runs only on replaced document.

This is a very subtle corner case and I think this isn't violating the contract
of extensions.

-          hasReceivedFirstMessage = true;
-          // Step one: Empty document where the JavaScript code was executed.
-          checkFirstMessageEquals('jsresult/')(request);
-        } else {
-          onRequest.removeListener(listener);
-          // Step 2: The empty document was replaced with the result of
-          // the evaluated JavaScript code.
-          checkFirstMessageEquals('jsresult/something')(request);
-          chrome.test.succeed();
-        }
+        onRequest.removeListener(listener);
+        // The empty document was replaced with the result of the evaluated
+        // JavaScript code.
+        checkFirstMessageEquals('jsresult/something')(request);
+        chrome.test.succeed();
       });
       chrome.test.log('Creating tab...');
       var test_url =