Implement HiDPI support in Pepper dev interface

ppapi/tests/test_graphics_2d.h

Index: ppapi/tests/test_graphics_2d.h
diff --git a/ppapi/tests/test_graphics_2d.h b/ppapi/tests/test_graphics_2d.h
index 86eb9a8985677079e6baee11e6856d941bf5df7e..f72561c987135d56ee6c92e8cc5f99fe515a47e1 100644
--- a/ppapi/tests/test_graphics_2d.h
+++ b/ppapi/tests/test_graphics_2d.h
@@ -78,6 +78,7 @@ class TestGraphics2D : public TestCase {
   std::string TestScroll();
   std::string TestReplace();
   std::string TestFlush();
+  std::string TestPrivate();
 
   // Used by the tests that access the C API directly.
   const PPB_Graphics2D* graphics_2d_interface_;