Cancel prerenders for pages that call window.print()

chrome/browser/prerender/prerender_message_filter.cc

Index: chrome/browser/prerender/prerender_message_filter.cc
diff --git a/chrome/browser/prerender/prerender_message_filter.cc b/chrome/browser/prerender/prerender_message_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a250b1eea042e95b0edaebf1a2373ec1a9ac566d
--- /dev/null
+++ b/chrome/browser/prerender/prerender_message_filter.cc
@@ -0,0 +1,61 @@
+// Copyright (c) 2011 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/prerender/prerender_message_filter.h"
+
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/prerender/prerender_final_status.h"
+#include "chrome/browser/prerender/prerender_manager.h"
+#include "chrome/browser/printing/print_job_manager.h"
+#include "chrome/browser/printing/printer_query.h"
+#include "chrome/common/print_messages.h"
+#include "content/browser/renderer_host/browser_render_process_host.h"
+
+namespace prerender {
+
+PrerenderMessageFilter::PrerenderMessageFilter(
+    BrowserRenderProcessHost* browser_render_process_host,
+    PrerenderManager* prerender_manager)
+    : browser_render_process_host_(browser_render_process_host),
+      prerender_manager_(prerender_manager) {
+}
+
+void PrerenderMessageFilter::OverrideThreadForMessage(
+    const IPC::Message& message, BrowserThread::ID* thread) {
+  if (message.type() == PrintHostMsg_ScriptedPrint::ID)
+    *thread = BrowserThread::UI;
+}
+
+bool PrerenderMessageFilter::OnMessageReceived(const IPC::Message& message,
+                                               bool* message_was_ok) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP_EX(PrerenderMessageFilter, message, *message_was_ok)
+    IPC_MESSAGE_HANDLER(PrintHostMsg_ScriptedPrint, OnScriptedPrint)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void PrerenderMessageFilter::OnScriptedPrint(
+    const PrintHostMsg_ScriptedPrint_Params& params,
+    PrintMsg_PrintPages_Params* settings) {

[cbentzel, 2011/05/13 12:00:28]

DCHECK that this on the UI thread? You'll get that anyway if you have a weak
pointer for PrerenderManager and call .get(), but it might be worth keeping.

[dominich, 2011/05/13 15:05:33]

Done.

+  // Destroy all prerenders for this RenderViewHost.
+  // The print query will be destroyed by the TabContents destruction.

[cbentzel, 2011/05/13 14:36:21]

BUG: The PrerenderContents may have gone away at this point in time because the
prerendered page was swapped in during the IO->UI transition. Don't cancel
printing in that case. 

[dominich, 2011/05/13 15:05:33]

Done.

+  prerender_manager_->DestroyPreloadForChildRouteIdPair(
+      std::make_pair(browser_render_process_host_->id(), params.routing_id),
+      FINAL_STATUS_WINDOW_PRINT);
+
+  // Shamelessly ripped from PrintViewManager to clean up the print worker.

[cbentzel, 2011/05/13 12:00:28]

Should this be abstracted to a separate function?

[dominich, 2011/05/13 15:05:33]

Done.

+  scoped_refptr<printing::PrinterQuery> printer_query;
+  g_browser_process->print_job_manager()->PopPrinterQuery(params.cookie,
+                                                          &printer_query);
+  if (printer_query.get()) {
+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE,
+        NewRunnableMethod(printer_query.get(),
+                          &printing::PrinterQuery::StopWorker));
+  }
+}
+
+}