Enable download page action for error page

chrome/browser/net/net_error_tab_helper.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/net/net_error_tab_helper.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/io_thread.h"
@@ skipping 125 matching lines @@
 
 bool NetErrorTabHelper::OnMessageReceived(
     const IPC::Message& message,
     content::RenderFrameHost* render_frame_host) {
   if (render_frame_host != web_contents()->GetMainFrame())
     return false;
 #if BUILDFLAG(ANDROID_JAVA_UI)
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(NetErrorTabHelper, message)
     IPC_MESSAGE_HANDLER(ChromeViewHostMsg_DownloadPageLater, DownloadPageLater)
+    IPC_MESSAGE_HANDLER(ChromeViewHostMsg_SetIsShowingDownloadButtonInErrorPage,
+                        SetIsShowingDownloadButtonInErrorPage)

[mmenke, 2017/01/03 16:20:10]

How can the browser process have a better idea of what's currently being
displayed in the error page than the code that's actually displaying stuff in
the error page?

[nasko, 2017/01/04 18:22:20]

nit: Usually IPC handlers have an On prefix.

[jianli, 2017/01/06 23:46:37]

Done.

[jianli, 2017/01/06 23:46:37]

I am not sure I fully understand this comment. The browser process has no idea
about what is being displayed in the error page. This is the reason we send an
IPC from the code in renderer process that does the actual display.

[mmenke, 2017/01/09 20:02:25]

Sorry, I was getting net_error_tab_helper confused with net_error_helper, and
trying to figure out why net_error_helper was getting an IPC telling it that it
was displaying an error page.

     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
   return handled;
 #else
   return false;
 #endif  // BUILDFLAG(ANDROID_JAVA_UI)
 }
 
 NetErrorTabHelper::NetErrorTabHelper(WebContents* contents)
     : WebContentsObserver(contents),
       network_diagnostics_bindings_(contents, this),
       is_error_page_(false),
       dns_error_active_(false),
       dns_error_page_committed_(false),
+#if BUILDFLAG(ANDROID_JAVA_UI)
+      is_showing_download_button_in_error_page_(false),
+#endif  // BUILDFLAG(ANDROID_JAVA_UI

[nasko, 2017/01/04 18:22:20]

nit: Missing closing parenthesis.

[jianli, 2017/01/06 23:46:37]

Done.

       dns_probe_status_(error_page::DNS_PROBE_POSSIBLE),
       weak_factory_(this) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   // If this helper is under test, it won't have a WebContents.
   if (contents)
     InitializePref(contents);
 }
 
 void NetErrorTabHelper::OnMainFrameDnsError() {
@@ skipping 46 matching lines @@
   if (!entry || entry->GetPageType() != content::PAGE_TYPE_ERROR)
     return;
 
   // Only download the page for HTTP/HTTPS URLs.
   GURL url(entry->GetVirtualURL());
   if (!url.SchemeIsHTTPOrHTTPS())
     return;
 
   DownloadPageLaterHelper(url);
 }
+
+void NetErrorTabHelper::SetIsShowingDownloadButtonInErrorPage(bool show) {
+  is_showing_download_button_in_error_page_ = show;
+}
 #endif  // BUILDFLAG(ANDROID_JAVA_UI)
 
 void NetErrorTabHelper::InitializePref(WebContents* contents) {
   DCHECK(contents);
 
   BrowserContext* browser_context = contents->GetBrowserContext();
   Profile* profile = Profile::FromBrowserContext(browser_context);
   resolve_errors_with_web_service_.Init(
       prefs::kAlternateErrorPagesEnabled,
       profile->GetPrefs());
@@ skipping 49 matching lines @@
   offline_pages::ClientId client_id(
       offline_pages::kAsyncNamespace, base::GenerateGUID());
   request_coordinator->SavePageLater(
       page_url, client_id, true /*user_requested*/,
       offline_pages::RequestCoordinator::RequestAvailability::
           ENABLED_FOR_OFFLINER);
 }
 #endif  // BUILDFLAG(ANDROID_JAVA_UI)
 
 }  // namespace chrome_browser_net