Refactoring: replace NULL by nullptr for pointers (2nd CL).

This CL mainly handles the pointer comparisons (== or !=).

BUG=angleproject:2001

Change-Id: I25ac3b61032e7ad91459a1c6541cadc87cf9b160
Reviewed-on: https://chromium-review.googlesource.com/483935
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/renderer/d3d/ProgramD3D.cpp b/src/libANGLE/renderer/d3d/ProgramD3D.cpp
index 4af20fc..11c76f9 100644
--- a/src/libANGLE/renderer/d3d/ProgramD3D.cpp
+++ b/src/libANGLE/renderer/d3d/ProgramD3D.cpp
@@ -122,8 +122,8 @@
 template <typename T>
 static inline void SetIfDirty(T *dest, const T &source, bool *dirtyFlag)
 {
-    ASSERT(dest != NULL);
-    ASSERT(dirtyFlag != NULL);
+    ASSERT(dest != nullptr);
+    ASSERT(dirtyFlag != nullptr);
 
     *dirtyFlag = *dirtyFlag || (memcmp(dest, &source, sizeof(T)) != 0);
     *dest      = source;