Enable download page action for error page

chrome/browser/net/net_error_tab_helper.cc

Index: chrome/browser/net/net_error_tab_helper.cc
diff --git a/chrome/browser/net/net_error_tab_helper.cc b/chrome/browser/net/net_error_tab_helper.cc
index 8b257b5fa2b42ac9f24499fff870ef4f334f88c8..675e6003f171e08c9ae6d99399317bfaf4f4eae0 100644
--- a/chrome/browser/net/net_error_tab_helper.cc
+++ b/chrome/browser/net/net_error_tab_helper.cc
@@ -143,6 +143,8 @@ bool NetErrorTabHelper::OnMessageReceived(
   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()
 
@@ -158,6 +160,9 @@ NetErrorTabHelper::NetErrorTabHelper(WebContents* contents)
       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);
@@ -224,6 +229,10 @@ void NetErrorTabHelper::DownloadPageLater() {
 
   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) {