Add automated testing to check for page size with scaling

components/printing/test/print_web_view_helper_browsertest.cc

Index: components/printing/test/print_web_view_helper_browsertest.cc
diff --git a/components/printing/test/print_web_view_helper_browsertest.cc b/components/printing/test/print_web_view_helper_browsertest.cc
index 279ae825f41acee18f4b86ca53c553085a9ae2ba..515a4e762ef1dfc1bf0e9510c7046a344073cc63 100644
--- a/components/printing/test/print_web_view_helper_browsertest.cc
+++ b/components/printing/test/print_web_view_helper_browsertest.cc
@@ -24,6 +24,7 @@
 #include "ipc/ipc_listener.h"
 #include "printing/features/features.h"
 #include "printing/print_job_constants.h"
+#include "printing/units.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebMouseEvent.h"
 #include "third_party/WebKit/public/platform/WebString.h"
@@ -210,8 +211,20 @@ class PrintWebViewHelperTestBase : public content::RenderViewTest {
   }
 #endif  // BUILDFLAG(ENABLE_PRINT_PREVIEW)
 
+#if defined(OS_WIN)
+  // Verifies that the correct page size was returned.
+  void VerifyPrintedPageSize(
+      gfx::Size page_size,

[Lei Zhang, 2017/02/23 23:13:54]

One more pass by const ref.

[rbpotter, 2017/02/24 00:34:27]

Done.

+      PrintHostMsg_DidPrintPage::Param post_did_print_page_param) {

[Lei Zhang, 2017/02/23 23:13:54]

Make that 2?

[rbpotter, 2017/02/24 00:34:28]

Done.

+    gfx::Size page_size_received =
+        std::get<0>(post_did_print_page_param).page_size;
+    EXPECT_EQ(page_size.height(), page_size_received.height());

[Lei Zhang, 2017/02/23 23:13:54]

Fun fact, gfx::Size integrates well with gtest. Assuming we have a dependency on
the //ui/gfx:test_support target, which we probably already do, one can write:

gfx::Size a(100, 200);
gfx::Size b(300, 400);
EXPECT_EQ(a, b);

and at run time, that prints out:

Failure
Value of: b
  Actual: 300x400
Expected: a
Which is: 100x200

[rbpotter, 2017/02/24 00:34:27]

Done.

+    EXPECT_EQ(page_size.width(), page_size_received.width());
+  }
+#endif
+
   // Verifies whether the pages printed or not.
-  void VerifyPagesPrinted(bool printed) {
+  void VerifyPagesPrinted(bool printed, gfx::Size page_size = gfx::Size(0, 0)) {
     const IPC::Message* print_msg =
         render_thread_->sink().GetUniqueMessageMatching(
             PrintHostMsg_DidPrintPage::ID);
@@ -221,6 +234,10 @@ class PrintWebViewHelperTestBase : public content::RenderViewTest {
       PrintHostMsg_DidPrintPage::Param post_did_print_page_param;
       PrintHostMsg_DidPrintPage::Read(print_msg, &post_did_print_page_param);
       EXPECT_EQ(0, std::get<0>(post_did_print_page_param).page_number);
+#if defined(OS_WIN)
+      if (!page_size.IsEmpty())
+        VerifyPrintedPageSize(page_size, post_did_print_page_param);
+#endif
     }
   }
 
@@ -971,6 +988,38 @@ TEST_F(MAYBE_PrintWebViewHelperPreviewTest, OnPrintForPrintPreview) {
   VerifyPagesPrinted(true);
 }
 
+// Tests that when printing non-default scaling values, the page size returned
+// by PrintWebViewHelper is still the real physical page size. See
+// crbug.com/686384
+TEST_F(MAYBE_PrintWebViewHelperPreviewTest, OnPrintForPrintPreviewWithScaling) {
+  LoadHTML(kPrintPreviewHTML);
+
+  // Fill in some dummy values.
+  base::DictionaryValue dict;
+  CreatePrintSettingsDictionary(&dict);
+
+  // Media size
+  gfx::Size page_size_in = gfx::Size(240, 480);
+  float device_microns_per_unit =
+      (printing::kHundrethsMMPerInch * 10.0f) / printing::kDefaultPdfDpi;
+  int height_microns =
+      static_cast<int>(page_size_in.height() * device_microns_per_unit);
+  int width_microns =
+      static_cast<int>(page_size_in.width() * device_microns_per_unit);
+  auto media_size = base::MakeUnique<base::DictionaryValue>();
+  media_size->SetInteger(kSettingMediaSizeHeightMicrons, height_microns);
+  media_size->SetInteger(kSettingMediaSizeWidthMicrons, width_microns);
+
+  // Non default scaling value
+  dict.SetInteger(kSettingScaleFactor, 80);
+  dict.Set(kSettingMediaSize, media_size.release());
+
+  OnPrintForPrintPreview(dict);
+
+  VerifyPrintFailed(false);
+  VerifyPagesPrinted(true, page_size_in);
+}
+
 // Tests that printing from print preview fails and receiving error messages
 // through that channel all works.
 TEST_F(MAYBE_PrintWebViewHelperPreviewTest, OnPrintForPrintPreviewFail) {