Issue 4580 - Stop using ext.onMessage in background page

ext/background.js

Index: ext/background.js
===================================================================
--- a/ext/background.js
+++ b/ext/background.js
@@ -127,29 +127,29 @@
   };
 
   browser.tabs.onUpdated.addListener((tabId, changeInfo, tab) =>
   {
     if (changeInfo.status == "loading")
       ext.pages.onLoading._dispatch(new Page(tab));
   });
 
-  function createFrame(tabId, frameId)
+  function createFrame(tabId, frameId, url)
   {
     let frames = framesOfTabs.get(tabId);
     if (!frames)
     {
       frames = new Map();
       framesOfTabs.set(tabId, frames);
     }
 
     let frame = frames.get(frameId);
     if (!frame)
     {
-      frame = {};
+      frame = new Frame(tabId, frameId, url);
       frames.set(frameId, frame);
     }
 
     return frame;
   }
 
   function updatePageFrameStructure(frameId, tabId, url, parentFrameId)
   {
@@ -168,22 +168,21 @@
         // tabs that are already visible. Otherwise browser action changes get
         // overridden when Chrome automatically resets them on navigation.
         if (browser.runtime.lastError)
           ext.pages.onLoading._dispatch(page);
       });
     }
 
     // Update frame URL and parent in frame structure
-    let frame = createFrame(tabId, frameId);
-    frame.url = new URL(url);
+    let frame = createFrame(tabId, frameId, url);
 
     let parentFrame = framesOfTabs.get(tabId).get(parentFrameId);
     if (parentFrame)
-      frame.parent = parentFrame;
+      frame._setParent(parentFrame);
   }
 
   browser.webRequest.onHeadersReceived.addListener(details =>
   {
     // We have to update the frame structure when switching to a new
     // document, so that we process any further requests made by that
     // document in the right context. Unfortunately, we cannot rely
     // on webNavigation.onCommitted since it isn't guaranteed to fire
@@ -505,16 +504,43 @@
       if (windowId != browser.windows.WINDOW_ID_NONE)
         updateContextMenu();
     });
   }
 
 
   /* Web requests */
 
+  let Frame = ext.Frame = function(tabId, frameId, url)

[Manish Jethani, 2018/03/22 19:56:55]

So there's a Frame object now and it's used consistently everywhere.

+  {
+    this.id = frameId;
+
+    // In Edge requests from internal extension pages
+    // (protocol ms-browser-extension://) do no have a sender URL.
+    this.url = url ? new URL(url) : null;
+    this._tabId = tabId;
+  };
+  Frame.prototype = {
+    get parent()
+    {
+      if (typeof this._parent != "undefined")
+        return this._parent;
+
+      let frame = ext.getFrame(this._tabId, this.id);
+      if (frame)
+        return frame.parent;
+
+      return ext.getFrame(this._tabId, 0) || null;
+    },
+    _setParent(value)
+    {
+      this._parent = value;
+    }
+  };
+
   let framesOfTabs = new Map();
 
   ext.getFrame = (tabId, frameId) =>
   {
     let frames = framesOfTabs.get(tabId);
     return frames && frames.get(frameId);
   };
 
@@ -560,21 +586,21 @@
       {
         if (details && details.length > 0)
         {
           let frames = new Map();
           framesOfTabs.set(tab.id, frames);
 
           for (let detail of details)
           {
-            let frame = {url: new URL(detail.url)};
+            let frame = new Frame(tab.id, detail.frameId, detail.url);
             frames.set(detail.frameId, frame);
 
             if (detail.parentFrameId != -1)
-              frame.parent = frames.get(detail.parentFrameId);
+              frame._setParent(frames.get(detail.parentFrameId));
           }
         }
       });
     });
   });
 
   browser.webRequest.onBeforeRequest.addListener(details =>
   {
@@ -625,54 +651,16 @@
     }
 
     if (ext.webRequest.onBeforeRequest._dispatch(
         url, type, page, frame).includes(false))
       return {cancel: true};
   }, {urls: ["<all_urls>"]}, ["blocking"]);
 
 
-  /* Message passing */
-
-  browser.runtime.onMessage.addListener((message, rawSender, sendResponse) =>
-  {
-    let sender = {};
-
-    // Add "page" and "frame" if the message was sent by a content script.
-    // If sent by popup or the background page itself, there is no "tab".
-    if ("tab" in rawSender)
-    {
-      sender.page = new Page(rawSender.tab);
-      sender.frame = {
-        id: rawSender.frameId,
-        // In Edge requests from internal extension pages
-        // (protocol ms-browser-extension://) do no have a sender URL.
-        url: rawSender.url ? new URL(rawSender.url) : null,
-        get parent()
-        {
-          let frames = framesOfTabs.get(rawSender.tab.id);
-
-          if (!frames)
-            return null;
-
-          let frame = frames.get(rawSender.frameId);
-          if (frame)
-            return frame.parent || null;
-
-          return frames.get(0) || null;
-        }
-      };
-    }
-
-    return ext.onMessage._dispatch(
-      message, sender, sendResponse
-    ).includes(true);
-  });
-
-
   /* Storage */
 
   ext.storage = {
     get(keys, callback)
     {
       browser.storage.local.get(keys, callback);
     },
     set(key, value, callback)