Android: Use a ResourceThrottle to intercept GET downloads.

chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc

 // Copyright (c) 2012 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/renderer_host/chrome_resource_dispatcher_host_delegate.h"
 
 #include <string>
 
 #include "base/base64.h"
 #include "base/logging.h"
@@ skipping 43 matching lines @@
 #include "chrome/browser/managed_mode/managed_mode_resource_throttle.h"
 #endif
 
 #if defined(USE_SYSTEM_PROTOBUF)
 #include <google/protobuf/repeated_field.h>
 #else
 #include "third_party/protobuf/src/google/protobuf/repeated_field.h"
 #endif
 
 #if defined(OS_ANDROID)
+#include "chrome/browser/android/intercept_download_resource_throttle.h"
 #include "components/navigation_interception/intercept_navigation_delegate.h"
 #endif
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/login/merge_session_throttle.h"
 // TODO(oshima): Enable this for other platforms.
 #include "chrome/browser/renderer_host/offline_resource_throttle.h"
 #endif
 
 using content::BrowserThread;
@@ skipping 244 matching lines @@
     int child_id,
     int route_id,
     int request_id,
     bool is_content_initiated,
     bool must_download,
     ScopedVector<content::ResourceThrottle>* throttles) {
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(&NotifyDownloadInitiatedOnUI, child_id, route_id));
 
   // If it's from the web, we don't trust it, so we push the throttle on.

[joth, 2013/04/05 00:54:45]

sure you want your new throttle contained inside this if() too?

[nilesh, 2013/04/05 01:03:38]

Earlier this functionality was in DownloadResourceThrottle and this is the only
place when a DownloadResourceThrottle is created. So we are not changing which
requests will be intercepted. Am I missing something?

[asanka, 2013/04/05 16:57:35]

That's actually a good question. The DownloadResourceThrottle was only meant to
prevent carpet bombing and not as a generic go/no-go filter for downloads. The
|is_content_initiated| bit is there to separate downloads that were initiated by
content from other downloads.

|is_content_initated| is false for downloads initiated by:
- 'Save page' on a resource that's not text, HTML, CSS or javascript.
- 'Save URL' on a hyperlink.
- HTML5 Drag and drop.
- Downloads extension API.
- WebStore intaller.
- Plugin installer.

... is true for downloads initiated by:
- Navigation to a resource that can't be rendered (e.g. unhandled content type).
- Response requests download via 'Content-Disposition: attachment'.
- Other forced downloads (e.g. response is a user script).

It sounds like InterceptDownloadResourceThrottle wants to handle at least some
types of downloads for which |is_content_initiated| is false.

   if (is_content_initiated) {
     throttles->push_back(new DownloadResourceThrottle(
         download_request_limiter_, child_id, route_id, request_id,
         request->method()));
+#if defined(OS_ANDROID)
+    throttles->push_back(
+        new chrome::InterceptDownloadResourceThrottle(
+            request, child_id, route_id, request_id));
+#endif
   }
 
   // If this isn't a new request, we've seen this before and added the standard
   //  resource throttles already so no need to add it again.
   if (!request->is_pending()) {
     AppendStandardResourceThrottles(request,
                                     resource_context,
                                     child_id,
                                     route_id,
                                     ResourceType::MAIN_FRAME,
@@ skipping 282 matching lines @@
   int child_id, route_id;
   if (!prerender::PrerenderManager::DoesURLHaveValidScheme(redirect_url) &&
       ResourceRequestInfo::ForRequest(request)->GetAssociatedRenderView(
           &child_id, &route_id) &&
       prerender_tracker_->IsPrerenderingOnIOThread(child_id, route_id)) {
     prerender_tracker_->TryCancel(
         child_id, route_id, prerender::FINAL_STATUS_UNSUPPORTED_SCHEME);
     request->Cancel();
   }
 }