Initial error handling code

src/core/SkScalerContext.cpp

Index: src/core/SkScalerContext.cpp
diff --git a/src/core/SkScalerContext.cpp b/src/core/SkScalerContext.cpp
index 83cf8f80064aaf2c9c043ba72a52939a4864c05e..a0dbe0e023510b92a01b56b9130b6d4ac9186b09 100644
--- a/src/core/SkScalerContext.cpp
+++ b/src/core/SkScalerContext.cpp
@@ -66,15 +66,43 @@ void SkGlyph::zeroMetrics() {
     #define DUMP_RECx
 #endif
 
-static SkFlattenable* load_flattenable(const SkDescriptor* desc, uint32_t tag,
-                                       SkEffectType et) {
-    SkFlattenable*  obj = NULL;
-    uint32_t        len;
-    const void*     data = desc->findEntry(tag, &len);
+template <typename T> struct FlattenableInfo {};
+
+template <> struct FlattenableInfo<SkPathEffect> {
+    static SkPathEffect* read(SkOrderedReadBuffer& buffer) {
+        return buffer.readPathEffect();
+    }
+    static uint32_t getTag() {
+        return kPathEffect_SkDescriptorTag;
+    }
+};
+
+template <> struct FlattenableInfo<SkMaskFilter> {
+    static SkMaskFilter* read(SkOrderedReadBuffer& buffer) {
+        return buffer.readMaskFilter();
+    }
+    static uint32_t getTag() {
+        return kMaskFilter_SkDescriptorTag;
+    }
+};
+
+template <> struct FlattenableInfo<SkRasterizer> {
+    static SkRasterizer* read(SkOrderedReadBuffer& buffer) {
+        return buffer.readRasterizer();
+    }
+    static uint32_t getTag() {
+        return kRasterizer_SkDescriptorTag;
+    }
+};
+
+template <typename T> T* load_flattenable(const SkDescriptor* desc) {
+    T*          obj = NULL;
+    uint32_t    len;
+    const void* data = desc->findEntry(FlattenableInfo<T>::getTag(), &len);
 
     if (data) {
-        SkOrderedReadBuffer   buffer(data, len);
-        obj = buffer.readFlattenable(et);
+        SkOrderedReadBuffer buffer(data, len);
+        obj = FlattenableInfo<T>::read(buffer);
         SkASSERT(buffer.offset() == buffer.size());
     }
     return obj;
@@ -85,9 +113,9 @@ SkScalerContext::SkScalerContext(SkTypeface* typeface, const SkDescriptor* desc)
 
     , fBaseGlyphCount(0)
     , fTypeface(SkRef(typeface))
-    , fPathEffect(static_cast<SkPathEffect*>(load_flattenable(desc, kPathEffect_SkDescriptorTag, kPathEffect_SkEffectType)))
-    , fMaskFilter(static_cast<SkMaskFilter*>(load_flattenable(desc, kMaskFilter_SkDescriptorTag, kMaskFilter_SkEffectType)))
-    , fRasterizer(static_cast<SkRasterizer*>(load_flattenable(desc, kRasterizer_SkDescriptorTag, kRasterizer_SkEffectType)))
+    , fPathEffect(load_flattenable<SkPathEffect>(desc))
+    , fMaskFilter(load_flattenable<SkMaskFilter>(desc))
+    , fRasterizer(load_flattenable<SkRasterizer>(desc))
 
       // Initialize based on our settings. Subclasses can also force this.
     , fGenerateImageFromPath(fRec.fFrameWidth > 0 || fPathEffect != NULL || fRasterizer != NULL)