Detect presence of dwrite_1.h.

src/ports/SkScalerContext_win_dw.cpp

Index: src/ports/SkScalerContext_win_dw.cpp
diff --git a/src/ports/SkScalerContext_win_dw.cpp b/src/ports/SkScalerContext_win_dw.cpp
index e72746a520e42b3093313940df64487de7f68d2b..7884b13259c42f1ef11eaded9792394aba6d75d0 100644
--- a/src/ports/SkScalerContext_win_dw.cpp
+++ b/src/ports/SkScalerContext_win_dw.cpp
@@ -26,7 +26,9 @@
 #include "SkTypeface_win_dw.h"
 
 #include <dwrite.h>
-#include <dwrite_1.h>
+#if SK_HAS_DWRITE_1_H
+#  include <dwrite_1.h>
+#endif
 
 static bool isLCD(const SkScalerContext::Rec& rec) {
     return SkMask::kLCD16_Format == rec.fMaskFormat ||
@@ -524,6 +526,7 @@ void SkScalerContext_DW::generateFontMetrics(SkPaint::FontMetrics* metrics) {
     metrics->fFlags |= SkPaint::FontMetrics::kUnderlineThinknessIsValid_Flag;
     metrics->fFlags |= SkPaint::FontMetrics::kUnderlinePositionIsValid_Flag;
 
+#if SK_HAS_DWRITE_1_H
     if (fTypeface->fDWriteFontFace1.get()) {
         DWRITE_FONT_METRICS1 dwfm1;
         fTypeface->fDWriteFontFace1->GetMetrics(&dwfm1);
@@ -533,23 +536,28 @@ void SkScalerContext_DW::generateFontMetrics(SkPaint::FontMetrics* metrics) {
         metrics->fXMax = fTextSizeRender * SkIntToScalar(dwfm1.glyphBoxRight) / upem;
 
         metrics->fMaxCharWidth = metrics->fXMax - metrics->fXMin;
-    } else {
-        AutoTDWriteTable<SkOTTableHead> head(fTypeface->fDWriteFontFace.get());
-        if (head.fExists &&
-            head.fSize >= sizeof(SkOTTableHead) &&
-            head->version == SkOTTableHead::version1)
-        {
-            metrics->fTop = -fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->yMax) / upem;
-            metrics->fBottom = -fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->yMin) / upem;
-            metrics->fXMin = fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->xMin) / upem;
-            metrics->fXMax = fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->xMax) / upem;
+        return;
+    }
+#else
+#  pragma message("No dwrite_1.h is available, font metrics may be affected.")
+#endif
 
-            metrics->fMaxCharWidth = metrics->fXMax - metrics->fXMin;
-        } else {
-            metrics->fTop = metrics->fAscent;
-            metrics->fBottom = metrics->fDescent;
-        }
+    AutoTDWriteTable<SkOTTableHead> head(fTypeface->fDWriteFontFace.get());
+    if (head.fExists &&
+        head.fSize >= sizeof(SkOTTableHead) &&
+        head->version == SkOTTableHead::version1)
+    {
+        metrics->fTop = -fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->yMax) / upem;
+        metrics->fBottom = -fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->yMin) / upem;
+        metrics->fXMin = fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->xMin) / upem;
+        metrics->fXMax = fTextSizeRender * (int16_t)SkEndian_SwapBE16(head->xMax) / upem;
+
+        metrics->fMaxCharWidth = metrics->fXMax - metrics->fXMin;
+        return;
     }
+
+    metrics->fTop = metrics->fAscent;
+    metrics->fBottom = metrics->fDescent;
 }
 
 ///////////////////////////////////////////////////////////////////////////////