Apply Chromium style fixes.

This addresses several minor code quality issues that are validated
in Chromium, but not yet applied to ANGLE:

* constructors and destructors must be defined out-of-line
* auto is not allowed for simple pointer types
* use override everywhere instead of virtual
* virtual functions must also be defined out-of-line

Slightly reduces binary size for me (~2k on Win, 150k on Linux).

Bug: angleproject:1569
Change-Id: I073ca3365188caf5f29fb28d9eb207903c1843e6
Reviewed-on: https://chromium-review.googlesource.com/779959
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/compiler/preprocessor/Input.h b/src/compiler/preprocessor/Input.h
index d5f3858..8c7c7ee 100644
--- a/src/compiler/preprocessor/Input.h
+++ b/src/compiler/preprocessor/Input.h
@@ -18,6 +18,7 @@
 {
   public:
     Input();
+    ~Input();
     Input(size_t count, const char *const string[], const int length[]);
 
     size_t count() const { return mCount; }