Initialize font fallback when creating DWrite font manager

src/ports/SkFontMgr_win_dw.cpp

Index: src/ports/SkFontMgr_win_dw.cpp
diff --git a/src/ports/SkFontMgr_win_dw.cpp b/src/ports/SkFontMgr_win_dw.cpp
index 11afec3b53623205dad6612ab7cc0057c958181e..4a1659f843b440ad66eef341936feb37ebbc92a3 100644
--- a/src/ports/SkFontMgr_win_dw.cpp
+++ b/src/ports/SkFontMgr_win_dw.cpp
@@ -264,10 +264,13 @@ class SkFontMgr_DirectWrite : public SkFontMgr {
 public:
     /** localeNameLength must include the null terminator. */
     SkFontMgr_DirectWrite(IDWriteFactory* factory, IDWriteFontCollection* fontCollection,
-                          WCHAR* localeName, int localeNameLength)
+                          WCHAR* localeName, int localeNameLength, IDWriteFontFallback* fallback)
         : fFactory(SkRefComPtr(factory))
         , fFontCollection(SkRefComPtr(fontCollection))
         , fLocaleName(localeNameLength)
+#if SK_HAS_DWRITE_2_H
+        , fFontFallback(SkSafeRefComPtr(fallback))
+#endif
     {
 #if SK_HAS_DWRITE_2_H
         if (!SUCCEEDED(fFactory->QueryInterface(&fFactory2))) {
@@ -309,6 +312,7 @@ private:
     SkTScopedComPtr<IDWriteFactory> fFactory;
 #if SK_HAS_DWRITE_2_H
     SkTScopedComPtr<IDWriteFactory2> fFactory2;
+    SkTScopedComPtr<IDWriteFontFallback> fFontFallback;
 #endif
     SkTScopedComPtr<IDWriteFontCollection> fFontCollection;
     SkSMallocWCHAR fLocaleName;
@@ -762,9 +766,13 @@ SkTypeface* SkFontMgr_DirectWrite::onMatchFamilyStyleCharacter(const char family
     }
 
 #if SK_HAS_DWRITE_2_H
-    if (fFactory2.get()) {
-        SkTScopedComPtr<IDWriteFontFallback> fontFallback;
-        HRNM(fFactory2->GetSystemFontFallback(&fontFallback), "Could not get system fallback.");
+    if (fFactory2.get() || fFontFallback.get()) {

[bungeman-skia, 2016/03/01 16:09:24]

As this code stands, this test actually needs to be

if (fFactory2.get()) {

we're still using fFactory2 below to create the number substitution, so it must
be non-null. Whether or not fFontFallback is nullptr at this point does not make
a difference.

[Ilya Kulshin, 2016/03/07 23:42:04]

Acknowledged.

+        SkTScopedComPtr<IDWriteFontFallback> systemFontFallback;
+        IDWriteFontFallback* fontFallback = fFontFallback.get();
+        if (!fontFallback) {
+          HRNM(fFactory2->GetSystemFontFallback(&systemFontFallback), "Could not get system fallback.");
+          fontFallback = systemFontFallback.get();
+        }

[bungeman-skia, 2016/03/01 16:09:24]

This code (resolving an IDWriteFontFallback) should be done either in the in the
SkFontMgr_DirectWrite constructor or the SkFontMgr_New_DirectWrite factory.

Note that this means the above test (line 769, just after #if SK_HAS_DWRITE_2_H)
would become

if (fFactory2.get() && fFontFallback.get()) {

[Ilya Kulshin, 2016/03/07 23:42:04]

Moved it to SkfontMgr_New_DirectWrite, since that function already has other
code that does similar things.

 
         SkTScopedComPtr<IDWriteNumberSubstitution> numberSubstitution;
         HRNM(fFactory2->CreateNumberSubstitution(DWRITE_NUMBER_SUBSTITUTION_METHOD_NONE, nullptr, TRUE,
@@ -1068,7 +1076,8 @@ SkTypeface* SkFontStyleSet_DirectWrite::matchStyle(const SkFontStyle& pattern) {
 #include "SkTypeface_win.h"
 
 SK_API SkFontMgr* SkFontMgr_New_DirectWrite(IDWriteFactory* factory,
-                                            IDWriteFontCollection* collection) {
+                                            IDWriteFontCollection* collection,
+                                            IDWriteFontFallback* fallback) {
     if (nullptr == factory) {
         factory = sk_get_dwrite_factory();
         if (nullptr == factory) {
@@ -1099,7 +1108,7 @@ SK_API SkFontMgr* SkFontMgr_New_DirectWrite(IDWriteFactory* factory,
         };
     }
 
-    return new SkFontMgr_DirectWrite(factory, collection, localeName, localeNameLen);
+    return new SkFontMgr_DirectWrite(factory, collection, localeName, localeNameLen, fallback);
 }
 
 #include "SkFontMgr_indirect.h"