preprocessor: Miscellaneous cleanups

- Use full header paths in includes
- Use ASSERT instead of assert
- Use angle::NonCopyable instead of PP_DISALLOW_COPY_AND_ASSIGN
- Use range-for in a couple places
- Remove pp_utils.h

BUG=angleproject:1522

Change-Id: If107fef89e8465bca65cf664926d1051c5d1e232
Reviewed-on: https://chromium-review.googlesource.com/387212
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/compiler/preprocessor/Lexer.cpp b/src/compiler/preprocessor/Lexer.cpp
index 7c663ee..89cb3cf 100644
--- a/src/compiler/preprocessor/Lexer.cpp
+++ b/src/compiler/preprocessor/Lexer.cpp
@@ -4,7 +4,7 @@
 // found in the LICENSE file.
 //
 
-#include "Lexer.h"
+#include "compiler/preprocessor/Lexer.h"
 
 namespace pp
 {