add print to pdf for headless

headless/lib/browser/headless_devtools_manager_delegate.cc

Index: headless/lib/browser/headless_devtools_manager_delegate.cc
diff --git a/headless/lib/browser/headless_devtools_manager_delegate.cc b/headless/lib/browser/headless_devtools_manager_delegate.cc
index 3ecf23d9a473e4f2f30696383b7d91ba89ee068b..1ce13d834f341dea6a8e5be38e6f4fdf463a3ee1 100644
--- a/headless/lib/browser/headless_devtools_manager_delegate.cc
+++ b/headless/lib/browser/headless_devtools_manager_delegate.cc
@@ -7,6 +7,7 @@
 #include <string>
 #include <utility>
 
+#include "base/base64.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/devtools_agent_host.h"
 #include "content/public/browser/devtools_frontend_host.h"
@@ -14,6 +15,7 @@
 #include "headless/grit/headless_lib_resources.h"
 #include "headless/lib/browser/headless_browser_context_impl.h"
 #include "headless/lib/browser/headless_browser_impl.h"
+#include "headless/lib/browser/headless_print_manager.h"
 #include "headless/lib/browser/headless_web_contents_impl.h"
 #include "headless/public/devtools/domains/target.h"
 #include "ui/base/resource/resource_bundle.h"
@@ -55,6 +57,7 @@ std::unique_ptr<base::DictionaryValue> CreateErrorResponse(
   error_object->SetString(kErrorMessageParam, error_message);
 
   std::unique_ptr<base::DictionaryValue> response(new base::DictionaryValue());
+  response->SetInteger(kIdParam, command_id);
   response->Set(kErrorParam, std::move(error_object));
   return response;
 }
@@ -66,6 +69,23 @@ std::unique_ptr<base::DictionaryValue> CreateInvalidParamResponse(
       command_id, kErrorInvalidParam,
       base::StringPrintf("Missing or invalid '%s' parameter", param.c_str()));
 }
+
+void PDFCreated(content::DevToolsManagerDelegate::CommandCallback callback,
+                int command_id,
+                printing::HeadlessPrintManager::PrintResult print_result,
+                const std::string& data) {
+  std::unique_ptr<base::DictionaryValue> response;
+  if (print_result == printing::HeadlessPrintManager::kPrintSuccess)

[Lei Zhang, 2017/03/29 01:38:03]

nit: You need braces when the body is multi-line.

[jzfeng, 2017/03/29 03:50:12]

Done.

+    response = CreateSuccessResponse(
+        command_id,
+        printing::HeadlessPrintManager::PDFContentsToDictionaryValue(data));
+  else
+    response = CreateErrorResponse(
+        command_id, kErrorServerError,
+        printing::HeadlessPrintManager::PrintResultToErrMsg(print_result));
+  callback.Run(std::move(response));
+}
+
 }  // namespace
 
 HeadlessDevToolsManagerDelegate::HeadlessDevToolsManagerDelegate(
@@ -79,6 +99,9 @@ HeadlessDevToolsManagerDelegate::HeadlessDevToolsManagerDelegate(
       &HeadlessDevToolsManagerDelegate::CreateBrowserContext;
   command_map_["Target.disposeBrowserContext"] =
       &HeadlessDevToolsManagerDelegate::DisposeBrowserContext;
+
+  async_command_map_["Page.printToPDF"] =
+      &HeadlessDevToolsManagerDelegate::PrintToPDF;
 }
 
 HeadlessDevToolsManagerDelegate::~HeadlessDevToolsManagerDelegate() {}
@@ -108,6 +131,30 @@ base::DictionaryValue* HeadlessDevToolsManagerDelegate::HandleCommand(
   return cmd_result.release();
 }
 
+bool HeadlessDevToolsManagerDelegate::HandleAsyncCommand(
+    content::DevToolsAgentHost* agent_host,
+    base::DictionaryValue* command,
+    CommandCallback callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  if (!browser_)
+    return false;

[Lei Zhang, 2017/03/29 01:38:03]

nit: add a blank line like after line 115.

[jzfeng, 2017/03/29 03:50:13]

Done.

+  int id;
+  std::string method;
+  if (!command->GetInteger("id", &id) ||
+      !command->GetString("method", &method)) {
+    return false;
+  }
+  auto find_it = async_command_map_.find(method);
+  if (find_it == async_command_map_.end())
+    return false;
+  AsyncCommandMemberFnPtr async_command_fn_ptr = find_it->second;
+  const base::DictionaryValue* params = nullptr;
+  command->GetDictionary("params", &params);
+  ((this)->*async_command_fn_ptr)(agent_host, id, params, callback);

[Lei Zhang, 2017/03/29 01:38:03]

nit: Do you need a parens around "this" ? Same for line 130.

[jzfeng, 2017/03/29 03:50:13]

Done.

+  return true;
+}
+
 scoped_refptr<content::DevToolsAgentHost>
 HeadlessDevToolsManagerDelegate::CreateNewTarget(const GURL& url) {
   HeadlessBrowserContext* context = browser_->GetDefaultBrowserContext();
@@ -131,6 +178,18 @@ std::string HeadlessDevToolsManagerDelegate::GetFrontendResource(
   return content::DevToolsFrontendHost::GetFrontendResource(path).as_string();
 }
 
+void HeadlessDevToolsManagerDelegate::PrintToPDF(
+    content::DevToolsAgentHost* agent_host,
+    int command_id,
+    const base::DictionaryValue* params,
+    CommandCallback callback) {
+  content::WebContents* web_contents = agent_host->GetWebContents();
+  content::RenderFrameHost* rfh = web_contents->GetMainFrame();
+
+  printing::HeadlessPrintManager::FromWebContents(web_contents)
+      ->GetPDFContents(rfh, base::Bind(&PDFCreated, callback, command_id));
+}
+
 std::unique_ptr<base::DictionaryValue>
 HeadlessDevToolsManagerDelegate::CreateTarget(
     int command_id,