Fix for "chrome://" links in PDFs.

chrome/browser/extensions/chrome_extension_web_contents_observer.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/chrome_extension_web_contents_observer.h"
 
 #include "chrome/browser/extensions/error_console/error_console.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/window_controller.h"
 #include "chrome/common/extensions/chrome_extension_messages.h"
+#include "chrome/common/url_constants.h"
 #include "content/public/browser/browser_context.h"
+#include "content/public/browser/child_process_security_policy.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/common/extension_messages.h"
 #include "extensions/common/extension_urls.h"
 
 using content::BrowserContext;
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(
     extensions::ChromeExtensionWebContentsObserver);
 
 namespace extensions {
 
 ChromeExtensionWebContentsObserver::ChromeExtensionWebContentsObserver(
     content::WebContents* web_contents)
     : ExtensionWebContentsObserver(web_contents) {}
 
 ChromeExtensionWebContentsObserver::~ChromeExtensionWebContentsObserver() {}
 
 void ChromeExtensionWebContentsObserver::RenderViewCreated(
     content::RenderViewHost* render_view_host) {
   ReloadIfTerminated(render_view_host);
+
+  // Some extensions use "chrome://favicon/" and "chrome://extension-icon" URLs.

[Charlie Reis, 2015/09/22 17:38:15]

Why are these cases handled here vs chrome://resources in
extension_web_contents_observer.cc?  I don't understand the difference.

[paulmeyer, 2015/09/22 22:13:57]

The reason was because the host constants are from different layers.
content::kChromeUIResourcesHost is in the content layer, while
chrome::kChromeUIFaviconHost and chrome::kChromeUIExtensionIconHost are in the
chrome layer (so I moved them out here).

However, all of these permissions are really only needed in Chrome, so I can
move it all to the chrome layer.

+  const Extension* extension = GetExtension(render_view_host);
+  if (extension) {
+    Manifest::Type type = extension->GetType();
+    if (type == Manifest::TYPE_EXTENSION ||
+        type == Manifest::TYPE_LEGACY_PACKAGED_APP ||
+        (type == Manifest::TYPE_PLATFORM_APP &&
+         extension->location() == Manifest::COMPONENT)) {

[Charlie Reis, 2015/09/22 17:38:15]

This block is subtle in terms of which types of extensions have this access. 
The comment above should elaborate on why these and not others.

[paulmeyer, 2015/09/22 22:13:56]

Done.

+      int process_id = render_view_host->GetProcess()->GetID();
+      content::ChildProcessSecurityPolicy::GetInstance()->GrantSchemeHost(
+          process_id, content::kChromeUIScheme, chrome::kChromeUIFaviconHost);
+      content::ChildProcessSecurityPolicy::GetInstance()->GrantSchemeHost(
+          process_id, content::kChromeUIScheme,
+          chrome::kChromeUIExtensionIconHost);
+    }
+  }
+
   ExtensionWebContentsObserver::RenderViewCreated(render_view_host);
 }
 
 bool ChromeExtensionWebContentsObserver::OnMessageReceived(
     const IPC::Message& message,
     content::RenderFrameHost* render_frame_host) {
   if (ExtensionWebContentsObserver::OnMessageReceived(message,
                                                       render_frame_host)) {
     return true;
   }
@@ skipping 52 matching lines @@
   // TODO(yoz): This reload doesn't happen synchronously for unpacked
   //            extensions. It seems to be fast enough, but there is a race.
   //            We should delay loading until the extension has reloaded.
   if (registry->GetExtensionById(extension_id, ExtensionRegistry::TERMINATED)) {
     ExtensionSystem::Get(browser_context())->
         extension_service()->ReloadExtension(extension_id);
   }
 }
 
 }  // namespace extensions