Documentation: C API comments in include/

include/c/sk_maskfilter.h

Index: include/c/sk_maskfilter.h
diff --git a/include/c/sk_maskfilter.h b/include/c/sk_maskfilter.h
index ce38605a85daa62f15f9e134b298796b1355871d..5c22a063914fff4d26e08d07dc6614ee17656ee2 100644
--- a/include/c/sk_maskfilter.h
+++ b/include/c/sk_maskfilter.h
@@ -22,9 +22,24 @@ typedef enum {
 
 SK_C_PLUS_PLUS_BEGIN_GUARD
 
+/**
+    Increment the reference count on the given sk_maskfilter_t. Must be
+    balanced by a call to sk_maskfilter_unref().
+*/
 void sk_maskfilter_ref(sk_maskfilter_t*);
+/**
+    Decrement the reference count. If the reference count is 1 before
+    the decrement, then release both the memory holding the
+    sk_maskfilter_t and any other associated resources.  New
+    sk_maskfilter_t are created with a reference count of 1.
+*/
 void sk_maskfilter_unref(sk_maskfilter_t*);
 
+/**
+    Create a blur maskfilter.
+    @param sk_blurstyle_t The SkBlurStyle to use
+    @param sigma Standard deviation of the Gaussian blur to apply. Must be > 0.
+*/
 sk_maskfilter_t* sk_maskfilter_new_blur(sk_blurstyle_t, float sigma);
 
 SK_C_PLUS_PLUS_END_GUARD