gl: Remove redundant methods/variables from GLSurfaceFormat

ui/gl/init/gl_factory_ozone.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gl/init/gl_factory.h"
 
 #include "base/logging.h"
 #include "base/trace_event/trace_event.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_context_stub.h"
@@ skipping 67 matching lines @@
   if (HasGLOzone())
     return GetGLOzone()->CreateSurfacelessViewGLSurface(window);
 
   return nullptr;
 }
 
 scoped_refptr<GLSurface> CreateOffscreenGLSurfaceWithFormat(
     const gfx::Size& size, GLSurfaceFormat format) {
   TRACE_EVENT0("gpu", "gl::init::CreateOffscreenGLSurface");
 
-  if (!format.IsDefault()) {
-    NOTREACHED() << "FATAL: Ozone only supports default-format surfaces.";
-    return nullptr;
-  }

[piman, 2017/03/22 21:31:36]

Is it ok to remove this check? Why?

[klausw, 2017/03/22 21:49:21]

Removing the check is *not* ok, we have a currently active bug where having this
check helped identify what's going on.

You could replace it with format.IsCompatible(GLSurfaceFormat()) or equivalent.
It's a bit less efficient than explicitly tracking changes away from default,
but I doubt it matters - surface creation is expensive, and a few extra
comparisons wouldn't be a big deal.

To avoid gratuitous construction just for comparison purposes, should we add a
GLSurfaceFormat::DEFAULT static const member or a static getter for something
equivalent?

[piman, 2017/03/22 21:59:35]

Meh. Default-constructing a GLSurfaceFormat on the stack is trivial compared to
even just the logging code, no need for fanciness here.

[Chandan, 2017/03/23 12:34:27]

Uploaded patch set 2 with format.IsCompatible(GLSurfaceFormat()).
PTAL.

-
   if (HasGLOzone())
     return GetGLOzone()->CreateOffscreenGLSurface(size);
 
   switch (GetGLImplementation()) {
     case kGLImplementationMockGL:
     case kGLImplementationStubGL:
       return InitializeGLSurface(new GLSurfaceStub);
     default:
       NOTREACHED();
   }
 
   return nullptr;
 }
 
 }  // namespace init
 }  // namespace gl