Move LinkResult to the gl:: namespace.

This is a derived type from gl::Error so makes sense to be there.
Also makes it more accessible than in ProgramImpl.h

BUG=angleproject:1897

Change-Id: Id41b13e5a072745d8c361057f5bef8f152e0452b
Reviewed-on: https://chromium-review.googlesource.com/522872
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/renderer/gl/ProgramGL.cpp b/src/libANGLE/renderer/gl/ProgramGL.cpp
index 54bf40c..337bc48 100644
--- a/src/libANGLE/renderer/gl/ProgramGL.cpp
+++ b/src/libANGLE/renderer/gl/ProgramGL.cpp
@@ -49,9 +49,9 @@
     mProgramID = 0;
 }
 
-LinkResult ProgramGL::load(const gl::Context *context,
-                           gl::InfoLog &infoLog,
-                           gl::BinaryInputStream *stream)
+gl::LinkResult ProgramGL::load(const gl::Context *context,
+                               gl::InfoLog &infoLog,
+                               gl::BinaryInputStream *stream)
 {
     preLink();
 
@@ -116,9 +116,9 @@
     mFunctions->programParameteri(mProgramID, GL_PROGRAM_SEPARABLE, separable ? GL_TRUE : GL_FALSE);
 }
 
-LinkResult ProgramGL::link(const gl::Context *context,
-                           const gl::VaryingPacking &packing,
-                           gl::InfoLog &infoLog)
+gl::LinkResult ProgramGL::link(const gl::Context *context,
+                               const gl::VaryingPacking &packing,
+                               gl::InfoLog &infoLog)
 {
     preLink();