Document SkString::resize(int) as destructive.

include/core/SkString.h

Index: include/core/SkString.h
diff --git a/include/core/SkString.h b/include/core/SkString.h
index ea73e0982389eba2e2fcf050b2485f608ea3c9a9..9229d808a63d00ab79e758d249f5cd08952daf41 100644
--- a/include/core/SkString.h
+++ b/include/core/SkString.h
@@ -178,6 +178,7 @@ public:
     char& operator[](size_t n) { return this->writable_str()[n]; }
 
     void reset();
+    /** Destructive resize, does not preserve contents. */
     void resize(size_t len) { this->set(NULL, len); }
     void set(const SkString& src) { *this = src; }
     void set(const char text[]);