Add a class to allocate small objects w/o extra calls to new.

src/core/SkBitmapProcShader.h

Index: src/core/SkBitmapProcShader.h
diff --git a/src/core/SkBitmapProcShader.h b/src/core/SkBitmapProcShader.h
index b7e60f1ca1075e2413e791ced221e1b9de3b3110..40d516d36cb1162675cce2c506b881161545a5a7 100644
--- a/src/core/SkBitmapProcShader.h
+++ b/src/core/SkBitmapProcShader.h
@@ -12,6 +12,7 @@
 
 #include "SkShader.h"
 #include "SkBitmapProcState.h"
+#include "SkStackAllocator.h"
 
 class SkBitmapProcShader : public SkShader {
 public:
@@ -48,4 +49,13 @@ private:
     typedef SkShader INHERITED;
 };
 
+// Commonly used allocator. It currently is only used to allocate up to 2 objects, and the largest
+// object we want to allocate without using the heap is an SkBitmapProcShader.
+typedef SkSmallAllocator<2, sizeof(SkBitmapProcShader)> SkTBlitterAllocator;
+
+// If alloc is non-NULL, it will be used to allocate the returned SkShader, and MUST outlive
+// the SkShader.
+SkShader* CreateBitmapShader(const SkBitmap& src, SkShader::TileMode, SkShader::TileMode,
+                             SkTBlitterAllocator* alloc);
+
 #endif