Issue 4364 - Drop support for Chrome 29-40 and remove legacy code

chrome/ext/background.js

Index: chrome/ext/background.js
===================================================================
--- a/chrome/ext/background.js
+++ b/chrome/ext/background.js
@@ -469,50 +469,40 @@
 
   chrome.webRequest.onBeforeRequest.addListener(function(details)
   {
-    // the high-level code isn't interested in requests that aren't related
-    // to a tab and since those can only be handled in Chrome, we ignore
-    // them here instead of in the browser independent high-level code.
-    if (details.tabId == -1)
+    // the high-level code isn't interested in requests that aren't
+    // related to a tab or requests loading a top-level document,
+    // those should never be blocked
+    if (details.tabId == -1 || details.type == "main_frame")
       return;
 
-    var isMainFrame = details.type == "main_frame" || (
-      // assume that the first request belongs to the top frame. Chrome 29
-      // may give the top frame the type "object" instead of "main_frame".
-      // https://code.google.com/p/chromium/issues/detail?id=281711
-      details.frameId == 0 && !(details.tabId in framesOfTabs)
-    );
+    // we are looking for the frame that contains the element that

[kzar, 2016/08/30 13:14:09]

Mind making this comment a bit clearer (or removing it) while at it? I find it
quite hard to understand.

[Sebastian Noack, 2016/09/09 14:39:50]

Well, this comment isn't new and it makes sense to me. We are looking for the
frame that contains the element this request belongs to. If that element is
loading a subdocument (e.g. if the element is an <iframe>), the frame that
contains it is indicated by the parentFrameId property. However, if for example
it's an <img> element, the frame that contains it is indicated by the frameId
property. Feel free to make a suggestion how to better phrase it.

[kzar, 2016/09/13 12:30:01]

Fair enough, well how about this?

"We are looking for the frame that contains the element which has triggered this
request. For most requests (e.g. images) we can just use the request's frame ID,
but for subdocument requests (e.g. iframes) we must instead use the request's
parent frame ID."

[Sebastian Noack, 2016/09/13 15:21:30]

Done.

[kzar, 2016/09/13 17:08:58]

Looks great, thanks.

+    // is about to load, however if a frame is loading the surrounding
+    // frame is indicated by parentFrameId instead of frameId
+    var frameId;
+    var requestType;
+    if (details.type == "sub_frame")
+    {
+      frameId = details.parentFrameId;
+      requestType = "SUBDOCUMENT";
+    }
+    else
+    {
+      frameId = details.frameId;
+      requestType = details.type.toUpperCase();
+    }
 
-    if (!isMainFrame)
+    var frame = ext.getFrame(details.tabId, frameId);
+    if (frame)
     {
-      // we are looking for the frame that contains the element that
-      // is about to load, however if a frame is loading the surrounding
-      // frame is indicated by parentFrameId instead of frameId
-      var frameId;
-      var requestType;
-      if (details.type == "sub_frame")
-      {
-        frameId = details.parentFrameId;
-        requestType = "SUBDOCUMENT";
-      }
-      else
-      {
-        frameId = details.frameId;
-        requestType = details.type.toUpperCase();
-      }
+      var results = ext.webRequest.onBeforeRequest._dispatch(
+        new URL(details.url),
+        requestType,
+        new Page({id: details.tabId}),
+        frame
+      );
 
-      var frame = ext.getFrame(details.tabId, frameId);
-      if (frame)
-      {
-        var results = ext.webRequest.onBeforeRequest._dispatch(
-          new URL(details.url),
-          requestType,
-          new Page({id: details.tabId}),
-          frame
-        );
-
-        if (results.indexOf(false) != -1)
-          return {cancel: true};
-      }
+      if (results.indexOf(false) != -1)
+        return {cancel: true};
     }
   }, {urls: ["http://*/*", "https://*/*"]}, ["blocking"]);