Allow for Skia to be built without dwrite 1.1

src/ports/SkTypeface_win_dw.h

Index: src/ports/SkTypeface_win_dw.h
diff --git a/src/ports/SkTypeface_win_dw.h b/src/ports/SkTypeface_win_dw.h
index 465db3446bfb3cc2568ac505dc26ae1a16270990..6508b9f3ac309dfe3192402c0c0562dfbf678c62 100644
--- a/src/ports/SkTypeface_win_dw.h
+++ b/src/ports/SkTypeface_win_dw.h
@@ -17,7 +17,9 @@
 #include "SkTypes.h"
 
 #include <dwrite.h>
+#ifndef SK_IGNORE_DWRITE_1_SUPPORT

[bungeman-skia, 2014/09/08 21:10:04]

Ick, I'm against adding yet another magic build level define. It's a really hard
sell for XP, maybe a bit less so for Vista.

dwrite.h: SDK7.0 (0x0601)
dwrite_1.h: SDK8.0 (0x0602)
dwrite_2.h: SDK8.1 (0x0603)

It looks like we could use winsdkver.h, (the casing of which changed from
WinSDKVer.h to winsdkver.h in SDK 7.1A) but avoid the madness that is
NTDDI_MAXVER which seems to be set to something semi-random with each SDK update
(it only actually matches the max supported NTDDI_VER in SDK7.1). As a result,
it seems like the easiest correct-ish thing to do here is put something like

#define SK_HAS_DWRITE_1 (WINVER_MAXVER >= 0x0602)

in SkDWrite.h and then use it like

#if SK_HAS_DWRITE_1 

in places like this. It would also be nice to #warn that you're building with
reduced functionality if you don't have the requisite support in your SDK. Note
that sometime soon-ish we will also end up doing something like this for color
support, since that requires dwrite_2.h.



I took a look at
http://lxr.mozilla.org/mozilla-central/source/build/autoconf/winsdk.m4 and it
seems rather silly, since it might as well just be

#define WINSDK_MAXVER NTDDI_VERSION_FROM_WIN32_WINNT(_WIN32_WINNT_MAXVER)

since, except for SDK7.1 that's what it's doing anyway, and for SDK7.1 it gives
the same result.

 #include <dwrite_1.h>
+#endif
 
 class SkFontDescriptor;
 struct SkScalerContextRec;
@@ -52,11 +54,13 @@ private:
         , fDWriteFont(SkRefComPtr(font))
         , fDWriteFontFace(SkRefComPtr(fontFace))
     {
+#ifndef SK_IGNORE_DWRITE_1_SUPPORT
         if (!SUCCEEDED(fDWriteFontFace->QueryInterface(&fDWriteFontFace1))) {
             // IUnknown::QueryInterface states that if it fails, punk will be set to NULL.
             // http://blogs.msdn.com/b/oldnewthing/archive/2004/03/26/96777.aspx
             SK_ALWAYSBREAK(NULL == fDWriteFontFace1.get());
         }
+#endif
     }
 
 public:
@@ -66,7 +70,9 @@ public:
     SkTScopedComPtr<IDWriteFontFamily> fDWriteFontFamily;
     SkTScopedComPtr<IDWriteFont> fDWriteFont;
     SkTScopedComPtr<IDWriteFontFace> fDWriteFontFace;
+#ifndef SK_IGNORE_DWRITE_1_SUPPORT
     SkTScopedComPtr<IDWriteFontFace1> fDWriteFontFace1;
+#endif
 
     static DWriteFontTypeface* Create(IDWriteFactory* factory,
                                       IDWriteFontFace* fontFace,