Remove the discrepencies between chrome and android_webview print

android_webview/browser/aw_printing_message_filter.cc

Index: android_webview/browser/aw_printing_message_filter.cc
diff --git a/android_webview/browser/aw_printing_message_filter.cc b/android_webview/browser/aw_printing_message_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..524aed81defd2325f4f842aa99ea802ff0fff989
--- /dev/null
+++ b/android_webview/browser/aw_printing_message_filter.cc
@@ -0,0 +1,86 @@
+// Copyright 2015 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 "android_webview/browser/aw_printing_message_filter.h"
+
+#include "android_webview/browser/renderer_host/print_manager.h"
+#include "android_webview/common/print_messages.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/web_contents.h"
+
+using content::BrowserThread;
+using content::WebContents;
+
+
+namespace android_webview {
+
+namespace {
+
+PrintManager* GetPrintManager(int render_process_id, int render_view_id) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  content::RenderViewHost* rvh = content::RenderViewHost::FromID(
+      render_process_id, render_view_id);
+  if (rvh == nullptr)
+    return nullptr;
+  WebContents* web_contents = WebContents::FromRenderViewHost(rvh);
+  if (web_contents == nullptr)
+    return nullptr;
+  return PrintManager::FromWebContents(web_contents);
+}
+
+} // namespace
+
+AwPrintingMessageFilter::AwPrintingMessageFilter(int render_process_id)
+    : BrowserMessageFilter(PrintMsgStart),
+      render_process_id_(render_process_id) {
+}
+
+AwPrintingMessageFilter::~AwPrintingMessageFilter() {
+}
+
+void AwPrintingMessageFilter::OverrideThreadForMessage(
+    const IPC::Message& message, BrowserThread::ID* thread) {
+  if (message.type() == PrintHostMsg_AllocateTempFileForPrinting::ID ||
+      message.type() == PrintHostMsg_TempFileForPrintingWritten::ID) {
+    *thread = BrowserThread::UI;
+  }
+}
+
+bool AwPrintingMessageFilter::OnMessageReceived(const IPC::Message& message) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(AwPrintingMessageFilter, message)
+    IPC_MESSAGE_HANDLER(PrintHostMsg_AllocateTempFileForPrinting,
+                        OnAllocateTempFileForPrinting)
+    IPC_MESSAGE_HANDLER(PrintHostMsg_TempFileForPrintingWritten,
+                        OnTempFileForPrintingWritten)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void AwPrintingMessageFilter::OnAllocateTempFileForPrinting(
+    int render_view_id,
+    base::FileDescriptor* temp_file_fd,
+    int* sequence_number) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  PrintManager* print_manager =
+      GetPrintManager(render_process_id_, render_view_id);
+  if (print_manager == nullptr)
+    return;
+  print_manager->OnAllocateTempFileForPrinting(temp_file_fd, sequence_number);
+}
+
+void AwPrintingMessageFilter::OnTempFileForPrintingWritten(
+    int render_view_id,
+    int sequence_number) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  PrintManager* print_manager =
+      GetPrintManager(render_process_id_, render_view_id);
+  if (print_manager == nullptr)
+    return;
+  print_manager->OnTempFileForPrintingWritten(sequence_number);
+}
+
+}  // namespace android_webview