Add popup layout tests with device scale factor

components/test_runner/test_runner.cc

Index: components/test_runner/test_runner.cc
diff --git a/components/test_runner/test_runner.cc b/components/test_runner/test_runner.cc
index ce011c06ba33822b5a1b3aef43c883ecd1aa4c91..f4b034a9f2fb4136e2f4e4c5778c925b4d6960b7 100644
--- a/components/test_runner/test_runner.cc
+++ b/components/test_runner/test_runner.cc
@@ -8,8 +8,10 @@
 #include <limits>
 #include <utility>
 
+#include "base/command_line.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "build/build_config.h"
 #include "components/test_runner/mock_credential_manager_client.h"
@@ -56,6 +58,7 @@
 #include "ui/gfx/geometry/rect_f.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/skia_util.h"
+#include "ui/gfx/switches.h"
 
 #if defined(__linux__) || defined(ANDROID)
 #include "third_party/WebKit/public/web/linux/WebFontRendering.h"
@@ -1701,7 +1704,15 @@ void TestRunner::Reset() {
     // Reset the default quota for each origin to 5MB
     delegate_->SetDatabaseQuota(5 * 1024 * 1024);
     delegate_->SetDeviceColorProfile("reset");
-    delegate_->SetDeviceScaleFactor(1);
+    base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+    double scale = 1;
+    if (command_line->HasSwitch(switches::kForceDeviceScaleFactor)) {
+      std::string value =
+          command_line->GetSwitchValueASCII(switches::kForceDeviceScaleFactor);
+      if (!base::StringToDouble(value, &scale))
+        scale = 1;
+    }
+    delegate_->SetDeviceScaleFactor(scale);
     delegate_->SetAcceptAllCookies(false);
     delegate_->SetLocale("");
     delegate_->UseUnfortunateSynchronousResizeMode(false);