Add sk_careful_memcpy to catch undefined behavior in memcpy.

include/core/SkTArray.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkTArray_DEFINED
 #define SkTArray_DEFINED
 
 #include "../private/SkTemplates.h"
 #include "SkTypes.h"
 
 #include <new>
 
 template <typename T, bool MEM_COPY = false> class SkTArray;
 
 namespace SkTArrayExt {
 
 template<typename T>
 inline void copy(SkTArray<T, true>* self, int dst, int src) {
     memcpy(&self->fItemArray[dst], &self->fItemArray[src], sizeof(T));
 }
 template<typename T>
 inline void copy(SkTArray<T, true>* self, const T* array) {
-    memcpy(self->fMemArray, array, self->fCount * sizeof(T));
+    if (array) {
+        memcpy(self->fMemArray, array, self->fCount * sizeof(T));
+    }
 }
 template<typename T>
 inline void copyAndDelete(SkTArray<T, true>* self, char* newMemArray) {

[tomhudson, 2015/12/08 16:31:40]

Oddly, this doesn't delete anything?

-    memcpy(newMemArray, self->fMemArray, self->fCount * sizeof(T));
+    if (self->fMemArray) {
+        memcpy(newMemArray, self->fMemArray, self->fCount * sizeof(T));
+    }
 }
 
 template<typename T>
 inline void copy(SkTArray<T, false>* self, int dst, int src) {
     new (&self->fItemArray[dst]) T(self->fItemArray[src]);
 }
 template<typename T>
 inline void copy(SkTArray<T, false>* self, const T* array) {
     for (int i = 0; i < self->fCount; ++i) {
         new (self->fItemArray + i) T(array[i]);
@@ skipping 508 matching lines @@
     SkSTArray& operator= (const INHERITED& array) {
         INHERITED::operator=(array);
         return *this;
     }
 
 private:
     SkAlignedSTStorage<N,T> fStorage;
 };
 
 #endif