Wrap all preprocessor code in the angle namespace.

BUG=836820
BUG=801364

Change-Id: I08b6a2f9f12b689e09df6efd916c313e71e8a051
Reviewed-on: https://chromium-review.googlesource.com/1028581
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
diff --git a/src/compiler/preprocessor/Input.cpp b/src/compiler/preprocessor/Input.cpp
index 0f2327b..073d671 100644
--- a/src/compiler/preprocessor/Input.cpp
+++ b/src/compiler/preprocessor/Input.cpp
@@ -11,6 +11,9 @@
 
 #include "common/debug.h"
 
+namespace angle
+{
+
 namespace pp
 {
 
@@ -127,3 +130,5 @@
 }
 
 }  // namespace pp
+
+}  // namespace angle