add print to pdf for headless

headless/app/headless_shell.cc

Index: headless/app/headless_shell.cc
diff --git a/headless/app/headless_shell.cc b/headless/app/headless_shell.cc
index d6d6adeb758a5ef06ce2821d3973911297b22c74..bf3f81823925abd963c5d94069def9f5d9c4f72a 100644
--- a/headless/app/headless_shell.cc
+++ b/headless/app/headless_shell.cc
@@ -5,6 +5,7 @@
 #include <memory>
 #include <sstream>
 #include <string>
+#include <utility>
 
 #include "base/base64.h"
 #include "base/base_switches.h"
@@ -32,6 +33,8 @@ namespace {
 const char kDevToolsHttpServerAddress[] = "127.0.0.1";
 // Default file name for screenshot. Can be overriden by "--screenshot" switch.
 const char kDefaultScreenshotFileName[] = "screenshot.png";
+// Default file name for pdf. Can be overriden by "--print-to-pdf" switch.
+const char kDefaultPDFFileName[] = "output.pdf";
 
 bool ParseWindowSize(std::string window_size, gfx::Size* parsed_window_size) {
   int width, height = 0;
@@ -255,6 +258,9 @@ void HeadlessShell::OnPageReady() {
   } else if (base::CommandLine::ForCurrentProcess()->HasSwitch(
                  switches::kScreenshot)) {
     CaptureScreenshot();
+  } else if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+                 switches::kPrintToPDF)) {
+    PrintToPDF();
   } else {
     Shutdown();
   }
@@ -319,73 +325,89 @@ void HeadlessShell::CaptureScreenshot() {
 
 void HeadlessShell::OnScreenshotCaptured(
     std::unique_ptr<page::CaptureScreenshotResult> result) {
+  WriteFile(switches::kScreenshot, kDefaultScreenshotFileName,
+            result->GetData());
+}
+
+void HeadlessShell::PrintToPDF() {
+  devtools_client_->GetPage()->GetExperimental()->PrintToPDF(
+      page::PrintToPDFParams::Builder().Build(),
+      base::Bind(&HeadlessShell::OnPDFCreated, weak_factory_.GetWeakPtr()));
+}
+
+void HeadlessShell::OnPDFCreated(
+    std::unique_ptr<page::PrintToPDFResult> result) {
+  if (!result) {

[Eric Seckler, 2017/03/29 11:21:19]

For consistency, could you add the same check to OnScreenshotCaptured? :)

[jzfeng, 2017/03/30 03:04:56]

Done.

+    LOG(ERROR) << "Print to PDF failed";
+    Shutdown();
+    return;
+  }
+  WriteFile(switches::kPrintToPDF, kDefaultPDFFileName, result->GetData());
+}
+
+void HeadlessShell::WriteFile(const std::string& switch_string,

[Eric Seckler, 2017/03/29 11:21:19]

nit: file_path_switch

[jzfeng, 2017/03/30 03:04:56]

Done.

+                              const std::string& default_file_name,
+                              const std::string& data) {

[Eric Seckler, 2017/03/29 11:21:19]

nit: base64_data

[jzfeng, 2017/03/30 03:04:56]

Done.

   base::FilePath file_name =
-      base::CommandLine::ForCurrentProcess()->GetSwitchValuePath(
-          switches::kScreenshot);
+      base::CommandLine::ForCurrentProcess()->GetSwitchValuePath(switch_string);
   if (file_name.empty()) {
-    file_name = base::FilePath().AppendASCII(kDefaultScreenshotFileName);
+    file_name = base::FilePath().AppendASCII(default_file_name);
   }
 
-  screenshot_file_proxy_.reset(
-      new base::FileProxy(browser_->BrowserFileThread().get()));
-  if (!screenshot_file_proxy_->CreateOrOpen(
+  file_proxy_.reset(new base::FileProxy(browser_->BrowserFileThread().get()));
+  if (!file_proxy_->CreateOrOpen(
           file_name, base::File::FLAG_CREATE_ALWAYS | base::File::FLAG_WRITE,
-          base::Bind(&HeadlessShell::OnScreenshotFileOpened,
-                     weak_factory_.GetWeakPtr(),
-                     base::Passed(std::move(result)), file_name))) {
+          base::Bind(&HeadlessShell::OnFileOpened, weak_factory_.GetWeakPtr(),
+                     data, file_name))) {
     // Operation could not be started.
-    OnScreenshotFileOpened(nullptr, file_name, base::File::FILE_ERROR_FAILED);
+    OnFileOpened("", file_name, base::File::FILE_ERROR_FAILED);

[Lei Zhang, 2017/03/29 05:30:15]

Pass in a std::string() instead of "". There's a few more in
HeadlessPrintManager. See https://crrev.com/193040 for the reason.

[jzfeng, 2017/03/30 03:04:56]

Done.

   }
 }
 
-void HeadlessShell::OnScreenshotFileOpened(
-    std::unique_ptr<page::CaptureScreenshotResult> result,
-    const base::FilePath file_name,
-    base::File::Error error_code) {
-  if (!screenshot_file_proxy_->IsValid()) {
-    LOG(ERROR) << "Writing screenshot to file " << file_name.value()
+void HeadlessShell::OnFileOpened(const std::string& data,
+                                 const base::FilePath file_name,
+                                 base::File::Error error_code) {
+  if (!file_proxy_->IsValid()) {
+    LOG(ERROR) << "Writing to file " << file_name.value()
                << " was unsuccessful, could not open file: "
                << base::File::ErrorToString(error_code);
     return;
   }
 
-  std::string decoded_png;
-  base::Base64Decode(result->GetData(), &decoded_png);
+  std::string decoded_data;
+  base::Base64Decode(data, &decoded_data);

[Lei Zhang, 2017/03/29 05:30:15]

base::Base64Decode() can fail, BTW.

[jzfeng, 2017/03/30 03:04:56]

Added error handling logic.

   scoped_refptr<net::IOBufferWithSize> buf =
-      new net::IOBufferWithSize(decoded_png.size());
-  memcpy(buf->data(), decoded_png.data(), decoded_png.size());
+      new net::IOBufferWithSize(decoded_data.size());
+  memcpy(buf->data(), decoded_data.data(), decoded_data.size());
 
-  if (!screenshot_file_proxy_->Write(
+  if (!file_proxy_->Write(
           0, buf->data(), buf->size(),
-          base::Bind(&HeadlessShell::OnScreenshotFileWritten,
-                     weak_factory_.GetWeakPtr(), file_name, buf->size()))) {
+          base::Bind(&HeadlessShell::OnFileWritten, weak_factory_.GetWeakPtr(),
+                     file_name, buf->size()))) {
     // Operation may have completed successfully or failed.
-    OnScreenshotFileWritten(file_name, buf->size(),
-                            base::File::FILE_ERROR_FAILED, 0);
+    OnFileWritten(file_name, buf->size(), base::File::FILE_ERROR_FAILED, 0);
   }
 }
 
-void HeadlessShell::OnScreenshotFileWritten(const base::FilePath file_name,
-                                            const int length,
-                                            base::File::Error error_code,
-                                            int write_result) {
+void HeadlessShell::OnFileWritten(const base::FilePath file_name,
+                                  const int length,
+                                  base::File::Error error_code,
+                                  int write_result) {
   if (write_result < length) {
     // TODO(eseckler): Support recovering from partial writes.
-    LOG(ERROR) << "Writing screenshot to file " << file_name.value()
+    LOG(ERROR) << "Writing to file " << file_name.value()
                << " was unsuccessful: " << net::ErrorToString(write_result);

[Eric Seckler, 2017/03/29 11:21:19]

ups, I think we should be using File::ErrorToString here:
https://cs.chromium.org/chromium/src/base/files/file.cc?type=cs&l=97

[jzfeng, 2017/03/30 03:04:56]

Done.

   } else {
-    LOG(INFO) << "Screenshot written to file " << file_name.value() << "."
-              << std::endl;
+    LOG(INFO) << "Written to file " << file_name.value() << ".";
   }
-  if (!screenshot_file_proxy_->Close(
-          base::Bind(&HeadlessShell::OnScreenshotFileClosed,
-                     weak_factory_.GetWeakPtr()))) {
+  if (!file_proxy_->Close(base::Bind(&HeadlessShell::OnFileClosed,
+                                     weak_factory_.GetWeakPtr()))) {
     // Operation could not be started.
-    OnScreenshotFileClosed(base::File::FILE_ERROR_FAILED);
+    OnFileClosed(base::File::FILE_ERROR_FAILED);
   }
 }
 
-void HeadlessShell::OnScreenshotFileClosed(base::File::Error error_code) {
+void HeadlessShell::OnFileClosed(base::File::Error error_code) {
   Shutdown();
 }
 
@@ -417,6 +439,11 @@ bool ValidateCommandLine(const base::CommandLine& command_line) {
                << "when remote debugging is enabled.";
     return false;
   }
+  if (command_line.HasSwitch(switches::kPrintToPDF)) {
+    LOG(ERROR) << "Print to PDF is disabled "
+               << "when remote debugging is enabled.";
+    return false;
+  }
   if (command_line.HasSwitch(switches::kTimeout)) {
     LOG(ERROR) << "Navigation timeout is disabled "
                << "when remote debugging is enabled.";