add local-matrix to shader::context

src/core/SkBitmapProcShader.h

Index: src/core/SkBitmapProcShader.h
diff --git a/src/core/SkBitmapProcShader.h b/src/core/SkBitmapProcShader.h
index 0a036d3189ed8b40473815f034b948cac8df1925..8d312564696a116c5f25c32e0501a3a380f59215 100644
--- a/src/core/SkBitmapProcShader.h
+++ b/src/core/SkBitmapProcShader.h
@@ -71,10 +71,7 @@ private:
 // an Sk3DBlitter in SkDraw.cpp
 // Note that some contexts may contain other contexts (e.g. for compose shaders), but we've not
 // yet found a situation where the size below isn't big enough.
-typedef SkSmallAllocator<3, sizeof(SkBitmapProcShader) +
-                            sizeof(SkBitmapProcShader::BitmapProcShaderContext) +
-                            sizeof(SkBitmapProcState) +
-                            sizeof(void*) * 2> SkTBlitterAllocator;
+typedef SkSmallAllocator<3, 768> SkTBlitterAllocator;
 
 // If alloc is non-NULL, it will be used to allocate the returned SkShader, and MUST outlive
 // the SkShader.