Add skstd::move and skstd::forward.

Since we can't use the c++11 standard library, re-implement the bits
we want to use now.

TBR=reed@google.com
The next CL is try to move SkTemplates into private.

Review URL: https://codereview.chromium.org/1273813002
diff --git a/include/private/SkTLogic.h b/include/private/SkTLogic.h
index d188242..2710d6d 100644
--- a/include/private/SkTLogic.h
+++ b/include/private/SkTLogic.h
@@ -18,6 +18,8 @@
 #ifndef SkTLogic_DEFINED
 #define SkTLogic_DEFINED
 
+#include <stdint.h>
+
 /** Represents a templated integer constant.
  *  Pre-C++11 version of std::integral_constant.
  */
@@ -108,4 +110,29 @@
     static const bool value = sizeof(func<T>(NULL)) == sizeof(uint8_t); \
 }
 
+namespace skstd {
+
+/** SkTRemoveReference<T>::type is the type of T with any top-level lvalue or rvalue removed. */
+template <typename T> struct remove_reference { typedef T type; };
+template <typename T> struct remove_reference<T&> { typedef T type; };
+template <typename T> struct remove_reference<T&&> { typedef T type; };
+template <typename T> using remove_reference_t = typename remove_reference<T>::type;
+
+/** SkTIsLValueReference<T>::value is true if the type T is an lvalue reference. */
+template <typename T> struct is_lvalue_reference : SkFalse {};
+template <typename T> struct is_lvalue_reference<T&> : SkTrue {};
+
+}  // namespace skstd
+
+/**
+ *  SkTIsConst<T>::value is true if the type T is const.
+ *  The type T is constrained not to be an array or reference type.
+ */
+template <typename T> struct SkTIsConst {
+    static T* t;
+    static uint16_t test(const volatile void*);
+    static uint32_t test(volatile void *);
+    static const bool value = (sizeof(uint16_t) == sizeof(test(t)));
+};
+
 #endif