SkXPS: clean up SkConstexprMath

src/xps/SkXPSDevice.cpp

Index: src/xps/SkXPSDevice.cpp
diff --git a/src/xps/SkXPSDevice.cpp b/src/xps/SkXPSDevice.cpp
index aef9dc8baf8659b751c966becb167a9ccd3adcda..a9bab8456cd9dec754622f321933e586adb76d61 100644
--- a/src/xps/SkXPSDevice.cpp
+++ b/src/xps/SkXPSDevice.cpp
@@ -202,10 +202,9 @@ HRESULT SkXPSDevice::createXpsThumbnail(IXpsOMPage* page,
         "Could not create thumbnail generator.");
 
     SkTScopedComPtr<IOpcPartUri> partUri;
-    static const size_t size = SkTUMax<
-        SK_ARRAY_COUNT(L"/Documents/1/Metadata/.png") + SK_DIGITS_IN(pageNum),
-        SK_ARRAY_COUNT(L"/Metadata/" L_GUID_ID L".png")
-    >::value;
+    constexpr size_t size = SkSMax(
+            SK_ARRAY_COUNT(L"/Documents/1/Metadata/.png") + SkDigitsIn<unsigned>(),
+            SK_ARRAY_COUNT(L"/Metadata/" L_GUID_ID L".png"));
     wchar_t buffer[size];
     if (pageNum > 0) {
         swprintf_s(buffer, size, L"/Documents/1/Metadata/%u.png", pageNum);

[bungeman-skia, 2016/05/23 15:04:49]

Eck, now that I look at these, I think this needs to be at least _swprintf_s_l
which takes a locale so we can make sure the numbers are formatted the way we
expect. For example the locale fa_IR will produce non-arabic-indic digits here
if it's the current locale on this thread. Anyhow, that's a separate issue from
this.

[hal.canary, 2016/05/23 16:55:39]

Acknowledged.

@@ -229,8 +228,8 @@ HRESULT SkXPSDevice::createXpsThumbnail(IXpsOMPage* page,
 
 HRESULT SkXPSDevice::createXpsPage(const XPS_SIZE& pageSize,
                                    IXpsOMPage** page) {
-    static const size_t size = SK_ARRAY_COUNT(L"/Documents/1/Pages/.fpage")
-                             + SK_DIGITS_IN(fCurrentPage);
+    constexpr size_t size = SK_ARRAY_COUNT(L"/Documents/1/Pages/.fpage")
+                            + SkDigitsIn<unsigned>();
     wchar_t buffer[size];
     swprintf_s(buffer, size, L"/Documents/1/Pages/%u.fpage",
                              this->fCurrentPage);