[imageloader] Make chrome://file-manager externally connectable

Allow chrome://file-manager to connect to the image loader. Note: this
assumes chrome://file-manager has enabled chrome.runtime.sendMessage.

Since the manifest.json "externally_connectable" permission is used to
allow chrome://file_manager access, we must now list all the extension
|ids| that are allowed to connect to the image loader extension in the
"externally_connectable" permission. The ids are taken from the static
ImageLoader.ALLOWED_CLIENT_ORIGINS list.

Also add 'chrome://file-manager' to ImageLoader.ALLOWED_CLIENT_ORIGINS
list, which is still used to allow (or block) connecting sources based
on their URL origin.

Bug: 1113981, 1123261
Change-Id: I96b0db1a0155510f95285cda8f5c7c62e6fece9b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2600433
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Alex Danilo <adanilo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#839653}

ui/file_manager/image_loader/image_loader.js

@@ -83,7 +83,6 @@ function ImageLoader() {
   });
 }
 
-
 /**
  * List of extensions allowed to perform image requests.
  *
@@ -94,6 +93,7 @@ ImageLoader.ALLOWED_CLIENT_ORIGINS = [
   'chrome-extension://hhaomjibdihmijegdhdafkllkbggdgoj',  // File Manager
   'chrome-extension://nlkncpkkdoccmpiclbokaimcnedabhhm',  // Gallery
   'chrome-extension://jcgeabjmjgoblfofpppfkcoakmfobdko',  // Video Player
+  'chrome://file-manager',  // File Manager SWA
 ];
 
 /**

ui/file_manager/image_loader/manifest.json

@@ -20,6 +20,16 @@
     "page": "background.html",
     "persistent": false
   },
+  "externally_connectable": {
+    "ids": [
+      "hhaomjibdihmijegdhdafkllkbggdgoj",  // File Manager
+      "nlkncpkkdoccmpiclbokaimcnedabhhm",  // Gallery
+      "jcgeabjmjgoblfofpppfkcoakmfobdko"   // Video Player
+    ],
+    "matches": [
+      "chrome://file-manager/*"  // File Manager SWA
+    ]
+  },
   "natively_connectable": ["com.google.holding_space_thumbnail_loader"],
   "web_accessible_resources": ["image_loader_client.js"]
 }