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.cpp b/src/libANGLE/renderer/renderer_utils.cpp
index 005ebf2..c7bfab2 100644
--- a/src/libANGLE/renderer/renderer_utils.cpp
+++ b/src/libANGLE/renderer/renderer_utils.cpp
@@ -413,7 +413,7 @@
     }
 }
 
-gl::Error IncompleteTextureSet::getIncompleteTexture(
+angle::Result IncompleteTextureSet::getIncompleteTexture(
     const gl::Context *context,
     gl::TextureType type,
     MultisampleTextureInitializer *multisampleInitializer,
@@ -422,7 +422,7 @@
     *textureOut = mIncompleteTextures[type].get();
     if (*textureOut != nullptr)
     {
-        return gl::NoError();
+        return angle::Result::Continue();
     }
 
     ContextImpl *implFactory = context->getImplementation();
@@ -472,7 +472,7 @@
 
     mIncompleteTextures[type].set(context, t.release());
     *textureOut = mIncompleteTextures[type].get();
-    return gl::NoError();
+    return angle::Result::Continue();
 }
 
 #define ANGLE_INSTANTIATE_SET_UNIFORM_MATRIX_FUNC(cols, rows)                            \