Add BW masks to random scaler context

src/fonts/SkRandomScalerContext.cpp

Index: src/fonts/SkRandomScalerContext.cpp
diff --git a/src/fonts/SkRandomScalerContext.cpp b/src/fonts/SkRandomScalerContext.cpp
index 0693682faa707dcdcb9609d75a3b31bec79fd7bd..799e51df820e5b9803e6a1aa55786420bd9c5caa 100644
--- a/src/fonts/SkRandomScalerContext.cpp
+++ b/src/fonts/SkRandomScalerContext.cpp
@@ -63,7 +63,7 @@ void SkRandomScalerContext::generateMetrics(SkGlyph* glyph) {
     // Here we will change the mask format of the glyph
     // NOTE this is being overridden by the base class
     SkMask::Format format;
-    switch (glyph->getGlyphID() % 3) {
+    switch (glyph->getGlyphID() % 4) {
         case 0:
             format = SkMask::kLCD16_Format;
             break;
@@ -73,6 +73,9 @@ void SkRandomScalerContext::generateMetrics(SkGlyph* glyph) {
         case 2:
             format = SkMask::kARGB32_Format;
             break;
+        case 3:
+            format = SkMask::kBW_Format;
+            break;
     }
 
     fProxy->getMetrics(glyph);
@@ -132,7 +135,7 @@ void SkRandomScalerContext::generateMetrics(SkGlyph* glyph) {
 
 void SkRandomScalerContext::generateImage(const SkGlyph& glyph) {
     SkMask::Format format = (SkMask::Format)glyph.fMaskFormat;
-    switch (glyph.getGlyphID() % 3) {
+    switch (glyph.getGlyphID() % 4) {
         case 0:
             format = SkMask::kLCD16_Format;
             break;
@@ -142,6 +145,9 @@ void SkRandomScalerContext::generateImage(const SkGlyph& glyph) {
         case 2:
             format = SkMask::kARGB32_Format;
             break;
+        case 3:
+            format = SkMask::kBW_Format;
+            break;
     }
     const_cast<SkGlyph&>(glyph).fMaskFormat = format;