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/gl/FramebufferGL.cpp b/src/libANGLE/renderer/gl/FramebufferGL.cpp
index c0ff1ea..c3b1913 100644
--- a/src/libANGLE/renderer/gl/FramebufferGL.cpp
+++ b/src/libANGLE/renderer/gl/FramebufferGL.cpp
@@ -619,13 +619,13 @@
     return (status == GL_FRAMEBUFFER_COMPLETE);
 }
 
-gl::Error FramebufferGL::syncState(const gl::Context *context,
-                                   const Framebuffer::DirtyBits &dirtyBits)
+angle::Result FramebufferGL::syncState(const gl::Context *context,
+                                       const gl::Framebuffer::DirtyBits &dirtyBits)
 {
     // Don't need to sync state for the default FBO.
     if (mIsDefault)
     {
-        return gl::NoError();
+        return angle::Result::Continue();
     }
 
     const FunctionsGL *functions = GetFunctionsGL(context);
@@ -720,7 +720,7 @@
                                                                getState());
     }
 
-    return gl::NoError();
+    return angle::Result::Continue();
 }
 
 GLuint FramebufferGL::getFramebufferID() const