Add a browser test that can communicate with the layout test framework and print pdfs.

chrome/browser/printing/print_preview_pdf_generated_browsertest.cc

Index: chrome/browser/printing/print_preview_pdf_generated_browsertest.cc
diff --git a/chrome/browser/printing/print_preview_pdf_generated_browsertest.cc b/chrome/browser/printing/print_preview_pdf_generated_browsertest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4dfb7056cd78e523dd83662a44b3fcb76833e8b9
--- /dev/null
+++ b/chrome/browser/printing/print_preview_pdf_generated_browsertest.cc
@@ -0,0 +1,672 @@
+// Copyright 2014 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 <cstdio>
+#include <iostream>
+#include <iterator>
+#include <limits>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "base/file_util.h"
+#include "base/files/file.h"
+#include "base/files/file_path.h"
+#include "base/files/scoped_temp_dir.h"
+#include "base/format_macros.h"
+#include "base/logging.h"
+#include "base/md5.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/numerics/safe_conversions.h"
+#include "base/path_service.h"
+#include "base/run_loop.h"
+#include "base/scoped_native_library.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.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 "net/base/filename_util.h"
+#include "printing/pdf_render_settings.h"
+#include "printing/units.h"
+#include "ui/events/keycodes/keyboard_codes.h"
+#include "ui/gfx/codec/png_codec.h"
+#include "ui/gfx/geometry/rect.h"
+#include "url/gurl.h"
+#include "ipc/ipc_message_macros.h"

[Lei Zhang, 2014/07/11 04:15:07]

this should be in alphabetical order

[ivandavid, 2014/07/16 20:06:33]

Done.

+
+#if defined(OS_POSIX)
+#define STDIN_STREAM std::cin
+#define STRING_TYPE std::string

[Lei Zhang, 2014/07/11 04:15:07]

Drop this and use base::FilePath::StringType.

[ivandavid, 2014/07/16 20:06:32]

Done.

+#elif defined(OS_WIN)
+#define STDIN_STREAM std::wcin

[Lei Zhang, 2014/07/11 04:15:07]

Have you actually tried this on Windows? I don't know if there is a version of
std::getline() that takes std::wcin.

[ivandavid, 2014/07/16 20:06:33]

I removed this code and just use std::cin. Then I convert the the string with
UTF8ToWide to put it in the correct format.

+#define STRING_TYPE std::wstring
+#endif
+
+using content::WebContents;
+using content::WebContentsObserver;
+
+// Number of color channels in a BGRA bitmap.
+const int kColorChannels = 4;
+const int kDpi = 300;
+
+// Message refers to the 'UILoaded' message from print_preview.js.
+// It gets sent either from onPreviewGenerationDone or from
+// onManipulateSettings_() in print_preview.js
+enum State {

[Lei Zhang, 2014/07/11 04:15:06]

Now that you added |is_already_pdf|, can you document which steps are only used
for printing non-pdf source?

[ivandavid, 2014/07/16 20:06:32]

Done.

+  // Waiting for the first message so the program can select Save as PDF
+  kWaitingToSendSaveAsPdf = 0,
+  // Waiting for the second message so the test can set the layout
+  kWaitingToSendLayoutSettings = 1,
+  // Waiting for the third message so the test can set the page numbers
+  kWaitingToSendPageNumbers = 2,
+  // Waiting for the forth message so the test can set the headers checkbox
+  kWaitingToSendHeadersAndFooters = 3,
+  // Waiting for the fifth message so the test can set the background checkbox
+  kWaitingToSendBackgroundColorsAndImages = 4,
+  // Waiting for the sixth message so the test can set the margins combobox
+  kWaitingToSendMargins = 5,
+  // Waiting for the final message so the program can save to PDF.
+  kWaitingForFinalMessage = 6,
+};
+
+// Settings for print preview. It reflects the current options provided by
+// print preview. If more options are added, more states should be added and
+// there should be more settings added to this struct.
+struct PrintPreviewSettings {
+  PrintPreviewSettings(bool is_portrait,
+                       std::string page_numbers,
+                       bool headers_and_footers,
+                       bool background_colors_and_images,
+                       printing::MarginType margins,

[Lei Zhang, 2014/07/11 04:15:06]

I'd put the entire file starting from line 70 in namespace printing, and drop
the printing::

[ivandavid, 2014/07/16 20:06:33]

Done.

+                       bool is_already_pdf)
+      : is_portrait(is_portrait),
+        page_numbers(page_numbers),
+        headers_and_footers(headers_and_footers),
+        background_colors_and_images(background_colors_and_images),
+        margins(margins),
+        is_already_pdf(is_already_pdf) {}
+
+  bool is_portrait;
+  std::string page_numbers;
+  bool headers_and_footers;
+  bool background_colors_and_images;
+  printing::MarginType margins;
+  bool is_already_pdf;
+};
+
+// Observes the print preview webpage. Once it observes the PreviewPageCount
+// message, will send a sequence of commands to the print preview dialog and
+// change the settings of the preview dialog.
+class PrintPreviewObserver : public WebContentsObserver {
+ public:
+  PrintPreviewObserver(WebContents* dialog, Browser* browser)

[Lei Zhang, 2014/07/11 04:15:07]

Can you make the parameters Browser* and then WebContents* ?

[ivandavid, 2014/07/16 20:06:32]

Done.

+      : WebContentsObserver(dialog),
+        browser_(browser),
+        state_(kWaitingToSendSaveAsPdf) {}
+
+  virtual ~PrintPreviewObserver() {}
+
+  // Sets closure for the observer so that it can end the loop.
+  void set_quit_closure(const base::Closure &closure) {
+    closure_ = closure;
+  }
+
+  // Actually stops the message loop so that the test can proceed.
+  void EndLoop() {
+    base::MessageLoop::current()->PostTask(FROM_HERE, closure_);
+  }
+
+  bool OnMessageReceived(const IPC::Message& message) OVERRIDE {
+    IPC_BEGIN_MESSAGE_MAP(PrintPreviewObserver, message)
+      IPC_MESSAGE_HANDLER(PrintHostMsg_DidGetPreviewPageCount,
+                          OnDidGetPreviewPageCount)
+    IPC_END_MESSAGE_MAP();
+    return false;
+  }
+
+  // Gets the web contents for the print preview dialog so that the UI and
+  // other elements can be accessed.
+  WebContents* GetDialog() {
+    WebContents* tab = browser_->tab_strip_model()->GetActiveWebContents();
+    printing::PrintPreviewDialogController* dialog_controller =
+        printing::PrintPreviewDialogController::GetInstance();
+    WebContents* web_contents =
+        dialog_controller->GetPrintPreviewForContents(tab);
+    return web_contents;
+  }
+
+  // Gets the PrintPreviewUI so that certain elements can be accessed.
+  PrintPreviewUI* GetUI() {
+    return static_cast<PrintPreviewUI*>(
+        GetDialog()->GetWebUI()->GetController());
+  }
+
+  // Calls native_layer.onManipulateSettingsForTest() and sends a dictionary
+  // value containing the type of setting and the value to set that settings
+  // to.
+  void ManipulatePreviewSettings() {
+    base::DictionaryValue script_argument;
+
+    if (state_ == kWaitingToSendSaveAsPdf) {
+      script_argument.SetBoolean("selectSaveAsPdfDestination", true);
+      state_ = settings_->is_already_pdf ?
+               kWaitingToSendPageNumbers : kWaitingToSendLayoutSettings;
+    } else if (state_ == kWaitingToSendLayoutSettings) {
+      script_argument.SetBoolean("layoutSettings.portrait",
+                                 settings_->is_portrait);
+      state_ = kWaitingToSendPageNumbers;
+    } else if (state_ == kWaitingToSendPageNumbers) {
+      script_argument.SetString("pageRange", settings_->page_numbers);
+      state_ = settings_->is_already_pdf ?
+               kWaitingForFinalMessage : kWaitingToSendHeadersAndFooters;
+    } else if (state_ == kWaitingToSendHeadersAndFooters) {
+      script_argument.SetBoolean("headersAndFooters",
+                                 settings_->headers_and_footers);
+      state_ = kWaitingToSendBackgroundColorsAndImages;
+    } else if (state_ == kWaitingToSendBackgroundColorsAndImages) {
+      script_argument.SetBoolean("backgroundColorsAndImages",
+                                 settings_->background_colors_and_images);
+      state_ = kWaitingToSendMargins;
+    } else if (state_ == kWaitingToSendMargins) {
+      script_argument.SetInteger("margins", settings_->margins);
+      state_ = kWaitingForFinalMessage;
+    } else if (state_ == kWaitingForFinalMessage) {
+      EndLoop();
+      return;
+    }
+
+    ASSERT_TRUE(!script_argument.empty());
+    GetUI()->web_ui()->CallJavascriptFunction(
+        "onManipulateSettingsForTest", script_argument);
+  }
+
+  // Saves the print preview settings to be sent to the print preview dialog.
+  void SetPrintPreviewSettings(const PrintPreviewSettings& settings) {
+    settings_.reset(new PrintPreviewSettings(settings));
+  }
+
+ private:
+  // Listens for messages from the print preview dialog. Specifically, it
+  // listens for 'UILoadedForTest' and 'UIFailedLoadingForTest.'
+  class UIDoneLoadingMessageHandler : public content::WebUIMessageHandler {
+   public:
+    explicit UIDoneLoadingMessageHandler(PrintPreviewObserver* observer)
+        : observer_(observer) {}
+
+    virtual ~UIDoneLoadingMessageHandler() {}
+
+    // When a setting has been set succesfully, this is called and the observer
+    // is told to send the next setting to be set.
+    void HandleDone(const base::ListValue* /* args */) {
+      ASSERT_TRUE(observer_);
+      observer_->ManipulatePreviewSettings();
+    }
+
+    // Ends the test because a setting was not set successfully. Called when
+    // this class hears 'UIFailedLoadingForTest.'
+    void HandleFailure(const base::ListValue* /* args */) {
+      FAIL();
+    }
+
+    // Sets up this class to listen for the UILoadedForTest and
+    // UIFailedLoadingForTest messages. These messages are sent by
+    // print_preview.js. On UILoadedForTest, a settings has been successfully
+    // set and its effects on the pdf have been finalized. On
+    // UIFailedLoadingForTest a setting has not been successfully set and the
+    // test should fail.
+    void RegisterMessages() OVERRIDE {
+      web_ui()->RegisterMessageCallback(
+          "UILoadedForTest",
+          base::Bind(&UIDoneLoadingMessageHandler::HandleDone,
+                     base::Unretained(this)));
+
+      web_ui()->RegisterMessageCallback(
+          "UIFailedLoadingForTest",
+          base::Bind(&UIDoneLoadingMessageHandler::HandleFailure,
+                     base::Unretained(this)));
+    }
+
+   private:
+    PrintPreviewObserver * const observer_;
+
+    DISALLOW_COPY_AND_ASSIGN(UIDoneLoadingMessageHandler);
+  };
+
+  // Called when the observer gets the IPC message stating that the page count
+  // is ready.
+  void OnDidGetPreviewPageCount(
+        const PrintHostMsg_DidGetPreviewPageCount_Params &params) {
+    WebContents* web_contents = GetDialog();
+    PrintPreviewUI* ui = GetUI();
+    ASSERT_TRUE(ui);
+    ASSERT_TRUE(ui->web_ui());
+    Observe(web_contents);
+    ASSERT_TRUE(web_contents);
+
+    // The web ui deallocates the memory for the handler when the web ui is
+    // destroyed so we don't have to worry about it.
+    ui->web_ui()->AddMessageHandler(new UIDoneLoadingMessageHandler(this));
+    ui->web_ui()->CallJavascriptFunction("onEnableManipulateSettingsForTest");
+  }
+
+  void DidCloneToNewWebContents(WebContents* old_web_contents,
+                                WebContents* new_web_contents) OVERRIDE {
+    Observe(new_web_contents);
+  }
+
+  void WebContentsDestroyed() OVERRIDE {
+    EndLoop();
+  }
+
+  Browser* browser_;
+  base::Closure closure_;

[Lei Zhang, 2014/07/11 04:15:07]

quit_closure_

[ivandavid, 2014/07/16 20:06:33]

Done.

+  scoped_ptr<PrintPreviewSettings> settings_;
+
+  // State of the observer. The state indicates what message it is to send

[Lei Zhang, 2014/07/11 04:15:07]

s/it is//

[ivandavid, 2014/07/16 20:06:32]

Done.

+  // next. The state advances whenever the message handler calls
+  // ManipulatePreviewSettings() on the observer.
+  State state_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrintPreviewObserver);
+};
+
+class PrintPreviewPdfGeneratedBrowserTest : public InProcessBrowserTest {
+ public:
+  PrintPreviewPdfGeneratedBrowserTest() {}
+  virtual ~PrintPreviewPdfGeneratedBrowserTest() {}
+
+  // Navigates to the given web page, then initiates print preview and waits
+  // for all the settings to be set.
+  void NavigateAndPreview(const STRING_TYPE& file_name,
+                          PrintPreviewSettings settings) {

[Lei Zhang, 2014/07/11 04:15:07]

const ref

[ivandavid, 2014/07/16 20:06:33]

Done.

+    print_preview_observer_->SetPrintPreviewSettings(settings);
+    base::FilePath path(file_name);
+    GURL gurl = net::FilePathToFileURL(path);
+
+    ui_test_utils::NavigateToURL(browser(), gurl);
+
+    base::RunLoop loop;
+    print_preview_observer_->set_quit_closure(loop.QuitClosure());
+    chrome::Print(browser());
+    loop.Run();
+  }
+
+  // Prints the web page to a PDF. NavigateAndPreview must be called first.
+  void Print() {
+    ASSERT_FALSE(pdf_file_save_path_.empty());
+    base::RunLoop loop;
+    print_preview_observer_->set_quit_closure(loop.QuitClosure());
+    print_preview_observer_->GetUI()->handler_->FileSelected(
+        pdf_file_save_path_, 0, NULL);
+    loop.Run();
+  }
+
+  // Initializes the pdf lib functions. Called once when browser test starts.
+  // Library is closed when the browser test is killed.

[Lei Zhang, 2014/07/11 04:15:06]

s/is killed/ends/

[ivandavid, 2014/07/16 20:06:32]

Done.

+  void InitPdfFunctions() {
+    base::FilePath pdf_module_path;
+
+    ASSERT_TRUE(PathService::Get(chrome::FILE_PDF_PLUGIN, &pdf_module_path));
+    ASSERT_TRUE(base::PathExists(pdf_module_path));
+    pdf_lib_.Reset(base::LoadNativeLibrary(pdf_module_path, NULL));
+
+    ASSERT_TRUE(pdf_lib_.is_valid());
+    pdf_to_bitmap_func_ =
+        reinterpret_cast<PDFPageToBitmapProc>(
+            pdf_lib_.GetFunctionPointer("RenderPDFPageToBitmap"));
+
+    pdf_doc_info_func_ =
+        reinterpret_cast<GetPDFDocInfoProc>(
+            pdf_lib_.GetFunctionPointer("GetPDFDocInfo"));
+
+    pdf_page_size_func_ =
+        reinterpret_cast<GetPDFPageSizeByIndexProc>(
+            pdf_lib_.GetFunctionPointer("GetPDFPageSizeByIndex"));
+
+    ASSERT_TRUE(pdf_to_bitmap_func_);
+    ASSERT_TRUE(pdf_doc_info_func_);
+    ASSERT_TRUE(pdf_page_size_func_);
+  }
+
+  // Converts the PDF to a PNG file so that the layout test can do an image
+  // diff on this image and a reference image.
+  void PdfToPng() {
+    std::string data;
+    int num_pages;
+    double max_width = 0;
+    std::vector<uint8_t> bitmap_data;
+    double total_height = 0;
+
+    ASSERT_TRUE(base::ReadFileToString(pdf_file_save_path_, &data));
+    ASSERT_TRUE(pdf_doc_info_func_(data.data(),
+                                   data.size(),
+                                   &num_pages,

[Lei Zhang, 2014/07/11 04:15:06]

Weren't we checking this is not negative?

[ivandavid, 2014/07/16 20:06:32]

Done.

[ivandavid, 2014/07/16 20:06:33]

Accidentally deleted that.

+                                   &max_width));
+
+    max_width = printing::ConvertPointsToPixelDouble(max_width);

[Lei Zhang, 2014/07/11 04:15:07]

I would make a new variable here named |max_width_in_pixels|. Having a variable
take on multiple units over its lifetime is confusing.

[ivandavid, 2014/07/16 20:06:33]

Done.

+
+    for (int i = 0; i < num_pages; ++i) {
+      double width, height;
+      bool autorotate = false;

[Lei Zhang, 2014/07/11 04:15:07]

Shouldn't this always be true? If width < height, then |pdf_to_bitmap_func_|
will do the "right thing" whether this is true or false. So why bother with this
variable at all?

[ivandavid, 2014/07/16 20:06:32]

Done.

[ivandavid, 2014/07/16 20:06:33]

I didn't realize that the |autorotate| parameter doesn't rotate in the case
where the page is already the correct dimensions. I removed this variable and
just the argument to true now.

+      ASSERT_TRUE(pdf_page_size_func_(
+          data.data(), data.size(), i, &width, &height));
+
+      width = printing::ConvertPointsToPixelDouble(width);

[Lei Zhang, 2014/07/11 04:15:07]

ditto for new variables.

[ivandavid, 2014/07/16 20:06:33]

Done.

+      height = printing::ConvertPointsToPixelDouble(height);
+
+      // The image needs to be rotated if the width is greater than the height.
+      // This is because when the image is printed to a pdf, it it is in
+      // landscape mode (or the document is just wide), it will be printed
+      // horizontally, not vertically. However, if it is printed onto a piece of
+      // paper, it would be rotated to be vertical. Therefore, the image has to
+      // be rotated here to reflect what will truly be printed.
+      if (width > height) {
+        std::swap<double>(width, height);
+        autorotate = true;
+      }
+
+      total_height += height;
+      gfx::Rect rect(width, height);
+      printing::PdfRenderSettings settings(rect, kDpi, true);
+
+      // TODO(ivandavid): Implement correct overflow detection. Need to check
+      // for signed multiplication overflow. Can't use size_t or any unsigned
+      // stuff, b/c internally everything in PdfRenderSettings is signed it
+      // seems.
+
+      int max_int = std::numeric_limits<int>::max();
+      if (settings.area().height() > max_int / settings.area().width() ||

[Lei Zhang, 2014/07/11 04:15:06]

The two comparisons in the if statement seem redundent.

[ivandavid, 2014/07/16 20:06:32]

Done.

[ivandavid, 2014/07/16 20:06:32]

I rewrote the overflow conditional. I first check to see if the width times the
amount of color channels overflows and then I check to see if the amount of
color channels times the area of the rectangle overflows.

+          settings.area().height() >
+              max_int / (kColorChannels * settings.area().width())) {

[Lei Zhang, 2014/07/11 04:15:07]

The multiplication can also overflow here.

[ivandavid, 2014/07/16 20:06:33]

Done.

+        FAIL() << "IMAGE SIZE IS TOO LARGE, DECREASE DIMENSIONS OR DPI.";

[Lei Zhang, 2014/07/11 04:15:06]

No need to be all caps.

[ivandavid, 2014/07/16 20:06:33]

Done.

+      }
+
+      std::vector<uint8_t> page_bitmap_data(
+          kColorChannels * settings.area().size().GetArea());
+
+      ASSERT_TRUE(pdf_to_bitmap_func_(data.data(),
+                                      data.size(),
+                                      i,
+                                      page_bitmap_data.data(),
+                                      settings.area().size().width(),
+                                      settings.area().size().height(),
+                                      settings.dpi(),
+                                      settings.dpi(),
+                                      autorotate));
+
+      // Must multiply width & max_width by number of color channels because

[Lei Zhang, 2014/07/11 04:15:06]

Refer to variables in comments as |foo|.

[Lei Zhang, 2014/07/11 04:15:07]

Shouldn't this be an internal detail to FillPng() ? Why should callers to
FillPng() have to recalculate their sizes?

[ivandavid, 2014/07/16 20:06:33]

Done.

[ivandavid, 2014/07/16 20:06:33]

Done.

+      // the bitmap stores individual bytes, not int32's.
+      if (width < max_width) {
+        FillPng(&page_bitmap_data,
+                width * kColorChannels,
+                max_width * kColorChannels,
+                settings.area().size().height());
+      }
+
+      bitmap_data.insert(bitmap_data.end(),
+                         page_bitmap_data.begin(),
+                         page_bitmap_data.end());
+    }
+
+    CreatePng(bitmap_data, max_width, total_height);
+  }
+
+  // Fills out a bitmap with whitespace so that the image will correctly fit
+  // within a PNG that is wider than the bitmap itself.
+  void FillPng(std::vector<uint8_t>* bitmap,
+               int current_width,
+               int desired_width,
+               int height) {
+    // Need to separate the iterator and the index. This is because the iterator
+    // will be rendered invalid whenever there is a resize, and since the bitmap
+    // might have to be widened significantly, this is likely to happen. Since
+    // vectors are being used, std::advance is really fast, so its ok.
+    ASSERT_TRUE(bitmap);
+    ASSERT_LE(current_width, desired_width);
+    const uint8_t kColorByte = 255;
+    size_t index = 0;
+    for (int i = 0; i < height; ++i, index = i * desired_width) {

[Lei Zhang, 2014/07/11 04:15:07]

The complexity of this algorithm using std::vector::insert() is really bad.
Please do this in O(N) time instead of O(N^2).

[ivandavid, 2014/07/16 20:06:32]

I think I came up with a better solution. I pre-allocated a vector with enough
size to fit in the large PNG. At the same time I filled every element with '255'
or rather the color white. I then went through the new vector and copied over
the old vector's contents into the correct spot. Then I just copy the new vector
data into the old one. I think this is O(n).

[ivandavid, 2014/07/16 20:06:33]

Done.

[Lei Zhang, 2014/07/17 00:30:36]

Sure, this uses 2*M memory, but you can get that down to 1*M later.

+      index += current_width - 1;
+      std::vector<uint8_t>::iterator iterator = bitmap->begin();
+      std::advance(iterator, index);
+      // 255,255,255,255 is white in BGRA
+      bitmap->insert(iterator, desired_width - current_width, kColorByte);
+    }
+  }
+
+  // Sends the PNG image to the layout test framework for comparison.
+  void SendPng() {
+    // Send image header and |hash_| to the layout test framework.
+    printf("Content-Type: image/png\n");
+    printf("ActualHash: %s\n", base::MD5DigestToBase16(hash_).data());

[Lei Zhang, 2014/07/11 04:15:07]

data() -> c_str();

http://www.cplusplus.com/reference/string/string/data/

[ivandavid, 2014/07/16 20:06:33]

Done.

+    printf("Content-Length: %" PRIuS "\n", output_.size());
+
+    for (size_t i = 0; i < output_.size(); ++i)
+      printf("%c", output_[i]);
+
+    printf("#EOF\n");
+    fflush(stdout);
+    fprintf(stderr, "#EOF\n");
+    fflush(stderr);
+  }
+
+  // Duplicates the tab that was created when the browser opened. This is done
+  // so that the observer can listen to the duplicated tab as soon as possible
+  // and start listening for messages related to print preview.
+  void DuplicateTab() {
+    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);
+  }
+
+  // Resets the test so that another web page can be printed. It also deletes
+  // the duplicated tab as it isn't needed anymore.
+  void Reset() {
+    output_.clear();
+    ASSERT_EQ(browser()->tab_strip_model()->count(), 2);
+    chrome::CloseTab(browser());
+    ASSERT_EQ(browser()->tab_strip_model()->count(), 1);
+  }
+
+  // Creates a temporary directory to store a text file that will be used for
+  // stdin to accept input from the layout test framework. A path for the pdf
+  // file is also created. The directory and files within it are automatically
+  // cleaned up once the test is killed.
+  void SetupStdinAndSavePath() {
+    // Sends a message to the layout test framework indicating indicating
+    // that the browser test has completed setting itself up. The layout
+    // test will then expect the file path for stdin.
+    base::FilePath tmp_path;
+    printf("#READY\n");
+    fflush(stdout);
+
+    ASSERT_TRUE(tmp_dir_.CreateUniqueTempDir());
+    ASSERT_TRUE(base::CreateTemporaryFileInDir(tmp_dir_.path(), &tmp_path));
+    ASSERT_TRUE(freopen(tmp_path.value().c_str(), "r", stdin));
+
+    pdf_file_save_path_ = tmp_dir_.path().AppendASCII("dummy.pdf");
+
+    // Send the file path to the layout test framework so that it can
+    // communicate with this browsertest.

[Lei Zhang, 2014/07/11 04:15:07]

browser test

[ivandavid, 2014/07/16 20:06:32]

Done.

+    printf("StdinPath: %s\n#EOF\n", tmp_path.value().c_str());
+    fflush(stdout);
+  }
+
+ private:
+  // Generates a png from bitmap data and stores it in |output_|.
+  void CreatePng(
+        const std::vector<uint8_t>& bitmap_data, int width, int height) {
+    std::string hash_data(bitmap_data.begin(), bitmap_data.end());
+    base::MD5Sum(
+        static_cast<const void*>(hash_data.data()), hash_data.size(), &hash_);
+
+    gfx::Rect png_rect(width, height);
+
+    // tEXtchecksum looks funny, but that's what the layout test framework
+    // expects.
+    std::string comment_title("tEXtchecksum\x00");
+    gfx::PNGCodec::Comment hash_comment(comment_title,
+                                        base::MD5DigestToBase16(hash_));
+
+    std::vector<gfx::PNGCodec::Comment> comments;
+    comments.push_back(hash_comment);
+
+    ASSERT_TRUE(gfx::PNGCodec::Encode(bitmap_data.data(),
+                                      gfx::PNGCodec::FORMAT_BGRA,
+                                      png_rect.size(),
+                                      png_rect.size().width() * kColorChannels,
+                                      false,
+                                      comments,
+                                      &output_));
+  }
+
+  scoped_ptr<PrintPreviewObserver> print_preview_observer_;
+  base::FilePath pdf_file_save_path_;
+
+  // These typedefs are function pointers to pdflib functions that give
+  // information about the PDF as a whole and about specific pages.
+
+  // Converts the PDF to a bitmap.
+  typedef bool (*PDFPageToBitmapProc)(const void* pdf_buffer,
+                                      int pdf_buffer_size,
+                                      int page_number,
+                                      void* bitmap_buffer,
+                                      int bitmap_width,
+                                      int bitmap_height,
+                                      int dpi_x,
+                                      int dpi_y,
+                                      bool autorotate);
+
+  // Gets the page count and maximum page width of the PDF in points.
+  typedef bool (*GetPDFDocInfoProc)(const void* pdf_buffer,
+                                    int buffer_size,
+                                    int* pages_count,
+                                    double* max_page_width);
+
+  // Gets the dimensions of a specific page within a PDF.
+  typedef bool (*GetPDFPageSizeByIndexProc)(const void* pdf_buffer,
+                                            int buffer_size,
+                                            int index,
+                                            double* width,
+                                            double* height);
+
+  // Instantiations of the function pointers described above.
+  PDFPageToBitmapProc pdf_to_bitmap_func_;
+  GetPDFDocInfoProc pdf_doc_info_func_;
+  GetPDFPageSizeByIndexProc pdf_page_size_func_;
+
+  // Used to open up the libpdf.so, which contains the functions above.
+  base::ScopedNativeLibrary pdf_lib_;
+
+  // Vector for storing the PNG to be sent to the layout test framework.
+  std::vector<unsigned char> output_;
+
+  // Image hash of the bitmap that is turned into a PNG. The hash is put into
+  // the PNG as a comment, as it is needed by the layout test framework.
+  base::MD5Digest hash_;
+
+  // Temporary directory for storing the pdf and the file for stdin.
+  base::ScopedTempDir tmp_dir_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrintPreviewPdfGeneratedBrowserTest);
+};
+
+IN_PROC_BROWSER_TEST_F(PrintPreviewPdfGeneratedBrowserTest,
+                       MANUAL_DummyTest) {
+  // What this code is supposed to do:
+  // -Setup communication with the layout test framework

[Lei Zhang, 2014/07/11 04:15:06]

Put a space after -

[ivandavid, 2014/07/16 20:06:32]

Done.

+  // -Print webpage to a pdf
+  // -Convert pdf to a png
+  // -Send png to layout test framework, where it doesn an image diff
+  //  on the image sent by this test and a reference image.
+  //
+  // Throughout this code, there will be printf statements. The layout test
+  // framework uses stdout to get data from the browser test and uses stdin
+  // to send data to the browser test. Calling printf("#EOF\n") indicates that
+  // whatever block of data that the test was expecting has been completely
+  // sent. Sometimes EOF is printed to stderr because the test will expect it
+  // from stderr in addition to stdout for certain blocks of data.
+  InitPdfFunctions();
+  SetupStdinAndSavePath();
+
+  // There is now way to determine how many tests are to be run ahead of time

[Lei Zhang, 2014/07/11 04:15:07]

now -> no

[ivandavid, 2014/07/16 20:06:32]

Done.

+  // without undesirable changes to the layout test framework. However, that is
+  // ok since whenever all the tests have been run, the layout test framework
+  // calls SIGKILL on this process, ending the test. This will end the while
+  // loop and cause the test to clean up after itself. For this to work, the
+  // browsertest must be run with '--single_process' not '--single-process.'
+  while (true) {
+    STRING_TYPE cmd;
+    std::getline(STDIN_STREAM, cmd);
+    if (cmd.empty()) {
+      while (STDIN_STREAM.eof()) {
+        STDIN_STREAM.clear();
+        std::getline(STDIN_STREAM, cmd);
+        if (!cmd.empty()) {
+          break;
+        }
+      }
+    }
+
+    DuplicateTab();
+
+    PrintPreviewSettings settings(
+        true,
+        "",
+        false,
+        false,
+        printing::DEFAULT_MARGINS,
+        cmd.find(".pdf") != STRING_TYPE::npos);
+
+    // Splits the command sent by the layout test framework. The first command
+    // is always the file path to use for the test. The rest isn't relevant,
+    // so it can be ignored. The separator for the commands is an apostrophe.
+    std::vector<STRING_TYPE> cmd_arguments;
+    base::SplitString(cmd, '\'', &cmd_arguments);
+    STRING_TYPE test_name(cmd_arguments[0]);

[Lei Zhang, 2014/07/11 04:15:06]

Assert the |cmd_arguments| size >= 1 before accessing the first element, or
assert it's 2 if that's always suppose to be 2.

[ivandavid, 2014/07/16 20:06:33]

Done.

+    NavigateAndPreview(test_name, settings);
+    Print();
+    PdfToPng();
+
+    // Message to the layout test framework indicating that it should start
+    // waiting for the image data, as there is no more text data to be read.
+    // There actually isn't any text data at all, however because the layout
+    // test framework requires it, a message has to be sent to stop it from
+    // waiting for this message and start waiting for the image data.
+    printf("#EOF\n");
+    fflush(stdout);
+
+    SendPng();
+    Reset();
+  }
+}