Let print-to-pdf obey source size scaling option in headless mode.

Bug: 724160
Change-Id: I9ede628f60f2ff32d09bcec9ef365db9246f4c98
Reviewed-on: https://chromium-review.googlesource.com/871046
Commit-Queue: Hidy Han <hidyhan@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Mustafa Emre Acer <meacer@chromium.org>
Reviewed-by: Eric Seckler <eseckler@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532965}

components/printing/common/print_messages.cc

@@ -95,7 +95,8 @@ PrintMsg_Print_Params::PrintMsg_Print_Params()
       header_template(),
       footer_template(),
       should_print_backgrounds(false),
-      printed_doc_type(printing::SkiaDocumentType::PDF) {}
+      printed_doc_type(printing::SkiaDocumentType::PDF),
+      prefer_css_page_size(false) {}
 
 PrintMsg_Print_Params::PrintMsg_Print_Params(
     const PrintMsg_Print_Params& other) = default;
@@ -126,6 +127,7 @@ void PrintMsg_Print_Params::Reset() {
   footer_template = base::string16();
   should_print_backgrounds = false;
   printed_doc_type = printing::SkiaDocumentType::PDF;
+  prefer_css_page_size = false;
 }
 
 PrintMsg_PrintPages_Params::PrintMsg_PrintPages_Params()

components/printing/common/print_messages.h

@@ -64,6 +64,7 @@ struct PrintMsg_Print_Params {
   base::string16 footer_template;
   bool should_print_backgrounds;
   printing::SkiaDocumentType printed_doc_type;
+  bool prefer_css_page_size;
 };
 
 struct PrintMsg_PrintPages_Params {
@@ -190,6 +191,9 @@ IPC_STRUCT_TRAITS_BEGIN(PrintMsg_Print_Params)
 
   // The document type of printed page(s) from render.
   IPC_STRUCT_TRAITS_MEMBER(printed_doc_type)
+
+  // True if page size defined by css should be preferred.
+  IPC_STRUCT_TRAITS_MEMBER(prefer_css_page_size)
 IPC_STRUCT_TRAITS_END()
 
 IPC_STRUCT_TRAITS_BEGIN(printing::PageRange)

components/printing/renderer/print_render_frame_helper.cc

@@ -1503,7 +1503,10 @@ void PrintRenderFrameHelper::Print(blink::WebLocalFrame* frame,
     if (!self)
       return;
 
-    print_settings.params.print_scaling_option = scaling_option;
+    print_settings.params.print_scaling_option =
+        print_settings.params.prefer_css_page_size
+            ? blink::kWebPrintScalingOptionSourceSize
+            : scaling_option;
     SetPrintPagesParams(print_settings);
     if (print_settings.params.dpi.IsEmpty() ||
         !print_settings.params.document_cookie) {

content/browser/devtools/protocol/page_handler.cc

@@ -631,6 +631,7 @@ void PageHandler::PrintToPDF(Maybe<bool> landscape,
                              Maybe<bool> ignore_invalid_page_ranges,
                              Maybe<String> header_template,
                              Maybe<String> footer_template,
+                             Maybe<bool> prefer_css_page_size,
                              std::unique_ptr<PrintToPDFCallback> callback) {
   callback->sendFailure(Response::Error("PrintToPDF is not implemented"));
   return;

content/browser/devtools/protocol/page_handler.h

@@ -124,6 +124,7 @@ class PageHandler : public DevToolsDomainHandler,
                   Maybe<bool> ignore_invalid_page_ranges,
                   Maybe<String> header_template,
                   Maybe<String> footer_template,
+                  Maybe<bool> prefer_css_page_size,
                   std::unique_ptr<PrintToPDFCallback> callback) override;
   Response StartScreencast(Maybe<std::string> format,
                            Maybe<int> quality,

headless/app/headless_shell.cc

@@ -487,6 +487,7 @@ void HeadlessShell::PrintToPDF() {
       page::PrintToPDFParams::Builder()
           .SetDisplayHeaderFooter(true)
           .SetPrintBackground(true)
+          .SetPreferCSSPageSize(true)
           .Build(),
       base::Bind(&HeadlessShell::OnPDFCreated, weak_factory_.GetWeakPtr()));
 }

headless/lib/browser/headless_devtools_manager_delegate.cc

@@ -273,6 +273,11 @@ std::unique_ptr<base::DictionaryValue> ParsePrintSettings(
   settings->margins_in_points.right =
       margin_right_in_inch * printing::kPointsPerInch;
 
+  if (const base::Value* prefer_css_page_size =
+          params->FindKey("preferCSSPageSize")) {
+    settings->prefer_css_page_size = prefer_css_page_size->GetBool();
+  }
+
   return nullptr;
 }
 #endif

headless/lib/browser/headless_print_manager.cc

@@ -40,7 +40,8 @@ struct HeadlessPrintManager::FrameDispatchHelper {
 };
 
 HeadlessPrintSettings::HeadlessPrintSettings()
-    : landscape(false),
+    : prefer_css_page_size(false),
+      landscape(false),
       display_header_footer(false),
       should_print_backgrounds(false),
       scale(1),
@@ -204,6 +205,7 @@ HeadlessPrintManager::GetPrintParamsFromSettings(
       base::UTF8ToUTF16(settings.header_template);
   print_params->params.footer_template =
       base::UTF8ToUTF16(settings.footer_template);
+  print_params->params.prefer_css_page_size = settings.prefer_css_page_size;
   return print_params;
 }
 

headless/lib/browser/headless_print_manager.h

@@ -27,6 +27,7 @@ struct HEADLESS_EXPORT HeadlessPrintSettings {
 
   gfx::Size paper_size_in_points;
   printing::PageMargins margins_in_points;
+  bool prefer_css_page_size;
 
   bool landscape;
   bool display_header_footer;

headless/lib/browser/headless_printing_unittest.cc

@@ -13,6 +13,18 @@
 
 namespace headless {
 
+TEST(ParsePrintSettingsTest, PreferCSSPageSize) {
+  HeadlessPrintSettings settings;
+  EXPECT_FALSE(settings.prefer_css_page_size);
+
+  auto params = std::make_unique<base::DictionaryValue>();
+  params->SetBoolean("preferCSSPageSize", true);
+  std::unique_ptr<base::DictionaryValue> response =
+      ParsePrintSettings(0, params.get(), &settings);
+  EXPECT_TRUE(settings.prefer_css_page_size);
+  EXPECT_EQ(nullptr, response);
+}
+
 TEST(ParsePrintSettingsTest, Landscape) {
   HeadlessPrintSettings settings;
   EXPECT_FALSE(settings.landscape);

third_party/WebKit/Source/core/inspector/browser_protocol.json

@@ -10128,6 +10128,12 @@
                             "description": "HTML template for the print footer. Should use the same format as the `headerTemplate`.",
                             "optional": true,
                             "type": "string"
+                        },
+                        {
+                            "name": "preferCSSPageSize",
+                            "description": "Whether or not to prefer page size as defined by css. Defaults to false,\nin which case the content will be scaled to fit the paper size.",
+                            "optional": true,
+                            "type": "boolean"
                         }
                     ],
                     "returns": [

third_party/WebKit/Source/core/inspector/browser_protocol.pdl

@@ -4633,6 +4633,9 @@ domain Page
       optional string headerTemplate
       # HTML template for the print footer. Should use the same format as the `headerTemplate`.
       optional string footerTemplate
+      # Whether or not to prefer page size as defined by css. Defaults to false,
+      # in which case the content will be scaled to fit the paper size.
+      optional boolean preferCSSPageSize
     returns
       # Base64-encoded pdf data.
       string data