Use angle::Result in front-end. (Part 1)

This covers most of the hot paths used in draw calls. Gives in the
order of a 5% reduction in draw call overhead.

Bug: angleproject:2491
Change-Id: I2d53afb1163eaceed61fb9cd9ce6c1267c85c0fa
Reviewed-on: https://chromium-review.googlesource.com/c/1258149
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/renderer/vulkan/RenderbufferVk.cpp b/src/libANGLE/renderer/vulkan/RenderbufferVk.cpp
index 40b529e..26059bd 100644
--- a/src/libANGLE/renderer/vulkan/RenderbufferVk.cpp
+++ b/src/libANGLE/renderer/vulkan/RenderbufferVk.cpp
@@ -118,21 +118,21 @@
     return gl::InternalError();
 }
 
-gl::Error RenderbufferVk::getAttachmentRenderTarget(const gl::Context * /*context*/,
-                                                    GLenum /*binding*/,
-                                                    const gl::ImageIndex & /*imageIndex*/,
-                                                    FramebufferAttachmentRenderTarget **rtOut)
+angle::Result RenderbufferVk::getAttachmentRenderTarget(const gl::Context *context,
+                                                        GLenum binding,
+                                                        const gl::ImageIndex &imageIndex,
+                                                        FramebufferAttachmentRenderTarget **rtOut)
 {
     ASSERT(mImage.valid());
     *rtOut = &mRenderTarget;
-    return gl::NoError();
+    return angle::Result::Continue();
 }
 
-gl::Error RenderbufferVk::initializeContents(const gl::Context *context,
-                                             const gl::ImageIndex &imageIndex)
+angle::Result RenderbufferVk::initializeContents(const gl::Context *context,
+                                                 const gl::ImageIndex &imageIndex)
 {
     UNIMPLEMENTED();
-    return gl::NoError();
+    return angle::Result::Continue();
 }
 
 }  // namespace rx