Use angle::Result in front-end (Part 8)

Refactors the gl::Texture class and a few related methods. Also reduces
binary size by up to 4k.

Bug: angleproject:2491
Change-Id: Ib9a69d7f507b0dce35abb17b90532f812bf43214
Reviewed-on: https://chromium-review.googlesource.com/c/1291845
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
diff --git a/src/libANGLE/renderer/renderer_utils.h b/src/libANGLE/renderer/renderer_utils.h
index b33cb50..7bcdb7e 100644
--- a/src/libANGLE/renderer/renderer_utils.h
+++ b/src/libANGLE/renderer/renderer_utils.h
@@ -236,8 +236,8 @@
 {
   public:
     virtual ~MultisampleTextureInitializer() {}
-    virtual gl::Error initializeMultisampleTextureToBlack(const gl::Context *context,
-                                                          gl::Texture *glTexture) = 0;
+    virtual angle::Result initializeMultisampleTextureToBlack(const gl::Context *context,
+                                                              gl::Texture *glTexture) = 0;
 };
 
 class IncompleteTextureSet final : angle::NonCopyable
@@ -248,10 +248,10 @@
 
     void onDestroy(const gl::Context *context);
 
-    gl::Error getIncompleteTexture(const gl::Context *context,
-                                   gl::TextureType type,
-                                   MultisampleTextureInitializer *multisampleInitializer,
-                                   gl::Texture **textureOut);
+    angle::Result getIncompleteTexture(const gl::Context *context,
+                                       gl::TextureType type,
+                                       MultisampleTextureInitializer *multisampleInitializer,
+                                       gl::Texture **textureOut);
 
   private:
     gl::TextureMap mIncompleteTextures;