Print Preview: Hook up the print button to initiate printing without displaying a print dialog.

chrome/browser/printing/printer_query.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// 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/printing/printer_query.h"
 
 #include "base/message_loop.h"
 #include "base/threading/thread_restrictions.h"
 #include "chrome/browser/printing/print_job_worker.h"
 
 namespace printing {
@@ skipping 88 matching lines @@
   worker_->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
       worker_.get(),
       &PrintJobWorker::GetSettings,
       is_print_dialog_box_shown_,
       parent_view,
       expected_page_count,
       has_selection,
       use_overlays));
 }
 
+void PrinterQuery::SetSettings(const std::string& new_settings,
+    CancelableTask* callback) {
+  DCHECK(!callback_.get());
+  DCHECK(worker_.get());
+  if (!worker_.get())
+    return;
+
+  // Lazy create the worker thread. There is one worker thread per print job.
+  if (!worker_->message_loop()) {
+    if (!worker_->Start()) {
+      if (callback) {
+        callback->Cancel();
+        delete callback;
+      }
+      NOTREACHED();
+      return;
+    }
+  }
+
+  callback_.reset(callback);
+  worker_->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
+      worker_.get(),
+      &PrintJobWorker::SetSettings,
+      new_settings));
+}
+
 void PrinterQuery::StopWorker() {
   if (worker_.get()) {
     // http://crbug.com/66082: We're blocking on the PrinterQuery's worker
     // thread.  It's not clear to me if this may result in blocking the current
     // thread for an unacceptable time.  We should probably fix it.
     base::ThreadRestrictions::ScopedAllowIO allow_io;
     worker_->Stop();
     worker_.reset();
   }
 }
 
 bool PrinterQuery::is_callback_pending() const {
   return callback_.get() != NULL;
 }
 
 bool PrinterQuery::is_valid() const {
   return worker_.get() != NULL;
 }
 
 }  // namespace printing