Added a test that currently is able to print to pdf.

chrome/browser/printing/print_preview_pdf_generated_browsertest.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 <string>
+
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/path_service.h"
+#include "base/run_loop.h"
+#include "base/strings/string_util.h"
+#include "chrome/app/chrome_command_ids.h"
+#include "chrome/browser/net/referrer.h"
+#include "chrome/browser/printing/print_preview_dialog_controller.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_commands.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "chrome/browser/ui/webui/print_preview/print_preview_handler.h"
+#include "chrome/browser/ui/webui/print_preview/print_preview_ui.h"
+#include "chrome/browser/ui/webui/print_preview/sticky_settings.h"
+#include "chrome/common/chrome_paths.h"
+#include "chrome/common/print_messages.h"
+#include "chrome/common/url_constants.h"
+#include "chrome/test/base/in_process_browser_test.h"
+#include "chrome/test/base/ui_test_utils.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_ui_message_handler.h"
+#include "content/public/common/page_transition_types.h"
+#include "content/public/test/browser_test_utils.h"
+#include "content/public/test/test_navigation_observer.h"
+#include "content/public/test/test_utils.h"
+#include "ui/events/keycodes/keyboard_codes.h"
+#include "url/gurl.h"
+#include "ipc/ipc_message_macros.h"
+
+using content::WebContents;
+using content::WebContentsObserver;
+
+class PrintPreviewObserver;
+class UIDoneLoadingMessageHandler;
+
+/* Need to split declarations & definitions due to forward declaration problem
+   */
+
+class PrintPreviewObserver : public WebContentsObserver {
+  public:
+    explicit PrintPreviewObserver(WebContents * dialog, Browser * browser);
+    virtual ~PrintPreviewObserver();
+
+    void set_quit_closure(const base::Closure &closure);
+    void EndLoop();
+    bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+    PrintPreviewUI * GetUI() {
+      return ui_;
+    }
+
+    WebContents * GetPreviewContents() {
+      return web_contents_;
+    }
+
+    void ManipulatePreviewSettings();

[Lei Zhang, 2014/06/17 00:53:26]

Add a comment to explain what this does.

+
+  private:
+    void OnDidGetPreviewPageCount(
+        const PrintHostMsg_DidGetPreviewPageCount_Params &params);
+
+    void DidCloneToNewWebContents(WebContents * old_web_contents,
+                                  WebContents * new_web_contents)
+                                  OVERRIDE;
+
+    void WebContentsDestroyed();
+
+    Browser * browser_;
+    base::Closure closure_;
+    WebContents * web_contents_;
+
+    PrintPreviewUI * ui_;
+
+    int count_;
+
+    DISALLOW_COPY_AND_ASSIGN(PrintPreviewObserver);
+};
+
+class UIDoneLoadingMessageHandler : public content::WebUIMessageHandler {
+  public:
+    explicit UIDoneLoadingMessageHandler(PrintPreviewObserver * observer);

[Lei Zhang, 2014/06/17 00:53:26]

nit: (all over) "Foo* foo", not "Foo * foo"

+    virtual ~UIDoneLoadingMessageHandler();
+    void HandleDone(const base::ListValue * /* args */);
+    void RegisterMessages() OVERRIDE;
+  private:
+    enum state { WAITING_FOR_FIRST_MESSAGE, WAITING_FOR_SECOND_MESSAGE };

[Lei Zhang, 2014/06/17 00:53:26]

Let's format it this way:

enum State {
  // Initial state, waiting for message X.
  WAITING_FOR_FIRST_MESSAGE,
  // Got message X, waiting for message Y.
  WAITING_FOR_SECOND_MESSAGE,
};

+    //After receiving the first message, the handler
+    //tells the observer to send the desired print settings to
+    //print_preview.js. After the second one, the pdf is saved
+
+    PrintPreviewObserver * observer_;
+    state state_;
+
+  DISALLOW_COPY_AND_ASSIGN(UIDoneLoadingMessageHandler);
+};
+
+UIDoneLoadingMessageHandler::UIDoneLoadingMessageHandler(
+    PrintPreviewObserver * observer) :
+  observer_(observer), state_(WAITING_FOR_FIRST_MESSAGE) {}
+
+UIDoneLoadingMessageHandler::~UIDoneLoadingMessageHandler() {
+  observer_ = NULL;
+}
+
+void UIDoneLoadingMessageHandler::RegisterMessages() OVERRIDE {
+  web_ui()->RegisterMessageCallback(
+  "UILoaded",
+  base::Bind(&UIDoneLoadingMessageHandler::HandleDone,
+             base::Unretained(this)));
+}
+
+void UIDoneLoadingMessageHandler::HandleDone(
+    const base::ListValue * /* args */) {
+  if (state_ == WAITING_FOR_FIRST_MESSAGE) {
+    state_ = WAITING_FOR_SECOND_MESSAGE;
+    /* send message to print_preview.js */
+    observer_->ManipulatePreviewSettings();
+  } else {
+    observer_->EndLoop();
+  }
+}
+
+PrintPreviewObserver::PrintPreviewObserver(
+    WebContents * dialog,
+    Browser * browser) :
+    WebContentsObserver(dialog), browser_(browser), count_(0) {}
+
+PrintPreviewObserver::~PrintPreviewObserver() {
+  browser_ = NULL;
+}
+
+void PrintPreviewObserver::set_quit_closure(const base::Closure &closure) {
+  closure_ = closure;
+}
+
+void PrintPreviewObserver::EndLoop() {
+  base::MessageLoop::current()->PostTask(FROM_HERE, closure_);
+}
+
+bool PrintPreviewObserver::OnMessageReceived(const IPC::Message& message)
+    OVERRIDE {
+  IPC_BEGIN_MESSAGE_MAP(PrintPreviewObserver, message)
+    IPC_MESSAGE_HANDLER(PrintHostMsg_DidGetPreviewPageCount,
+                        OnDidGetPreviewPageCount)
+    IPC_MESSAGE_UNHANDLED(break;)
+  IPC_END_MESSAGE_MAP();
+  return false;
+}
+
+void PrintPreviewObserver::OnDidGetPreviewPageCount(
+    const PrintHostMsg_DidGetPreviewPageCount_Params &params) {
+
+  WebContents * tab = browser_->tab_strip_model()->GetActiveWebContents();
+
+  ASSERT_TRUE(tab);
+
+  printing::PrintPreviewDialogController * dialog_controller =
+      printing::PrintPreviewDialogController::GetInstance();
+
+  ASSERT_TRUE(dialog_controller);
+
+  web_contents_ = dialog_controller->GetPrintPreviewForContents(tab);
+
+  ASSERT_TRUE(web_contents_ && printing::PrintPreviewDialogController::
+      IsPrintPreviewDialog(web_contents_));
+
+  ui_ = static_cast<PrintPreviewUI *>(web_contents_->GetWebUI()->
+      GetController());
+
+  ASSERT_TRUE(ui_);
+
+  ASSERT_TRUE(ui_->web_ui());
+
+  this->Observe(web_contents_);
+
+  UIDoneLoadingMessageHandler * handler = new UIDoneLoadingMessageHandler(this);
+
+  ui_->web_ui()->AddMessageHandler(handler);
+}
+
+void PrintPreviewObserver::ManipulatePreviewSettings() {
+  ui_->web_ui()->CallJavascriptFunction("onManipulateSettings");
+}
+
+void PrintPreviewObserver::DidCloneToNewWebContents(
+    WebContents * old_web_contents,
+    WebContents * new_web_contents)
+    OVERRIDE {
+  this->Observe(new_web_contents);
+}
+
+void PrintPreviewObserver::WebContentsDestroyed() {
+  this->EndLoop();
+}
+
+class PrintPreviewPdfGeneratedBrowserTest : public InProcessBrowserTest {
+  public:
+    PrintPreviewPdfGeneratedBrowserTest() {}
+    virtual ~PrintPreviewPdfGeneratedBrowserTest() {}
+
+    void NavigateAndPreview(std::string file_name) {
+      base::FilePath directory("printing");
+      base::FilePath file(file_name);
+
+      ui_test_utils::NavigateToURL(browser(),
+                                   ui_test_utils::GetTestUrl(directory, file));
+
+      base::RunLoop loop;
+      print_preview_observer_->set_quit_closure(loop.QuitClosure());
+      chrome::Print(browser());
+      loop.Run();
+    }
+
+    void Print() {
+      base::FilePath pdf_file_path;
+      ASSERT_TRUE(PathService::Get(chrome::DIR_TEST_DATA, &pdf_file_path));
+      pdf_file_path = pdf_file_path.AppendASCII("printing");
+      pdf_file_path = pdf_file_path.AppendASCII("dummy.pdf");

[Lei Zhang, 2014/06/17 00:53:26]

Actually, you don't want to litter DIR_TEST_DATA with files you created. You
probably should output them in a way that's somewhat compatible with the layout
test framework.

+
+      base::RunLoop loop;
+      print_preview_observer_->set_quit_closure(loop.QuitClosure());
+
+      print_preview_observer_->GetUI()->handler_->
+          FileSelected(pdf_file_path, 0, NULL);
+
+      loop.Run();
+    }
+
+  private:
+    virtual void SetUpOnMainThread() OVERRIDE {
+      WebContents * tab =
+          browser()->tab_strip_model()->GetActiveWebContents();
+      ASSERT_TRUE(tab);
+
+      print_preview_observer_.reset(new PrintPreviewObserver(tab, browser()));
+      chrome::DuplicateTab(browser());
+
+      WebContents * initiator_ =
+          browser()->tab_strip_model()->GetActiveWebContents();
+      ASSERT_TRUE(initiator_);
+      ASSERT_NE(tab, initiator_);
+    }
+
+    virtual void CleanUpOnMainThread() OVERRIDE {
+      print_preview_observer_.reset();
+    }
+
+    scoped_ptr<PrintPreviewObserver> print_preview_observer_;
+
+    DISALLOW_COPY_AND_ASSIGN(PrintPreviewPdfGeneratedBrowserTest);
+};
+
+IN_PROC_BROWSER_TEST_F(PrintPreviewPdfGeneratedBrowserTest, DummyTest) {
+    NavigateAndPreview("test2.html");
+    Print();
+}