Refactor context creation parameters into a struct.

ui/gl/gl_context_cgl.cc

 // Copyright (c) 2012 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/gl_context_cgl.h"
 
 #include <OpenGL/CGLRenderers.h>
 #include <OpenGL/CGLTypes.h>
 
 #include <memory>
@@ skipping 73 matching lines @@
   : GLContextReal(share_group),
     context_(nullptr),
     gpu_preference_(PreferIntegratedGpu),
     discrete_pixelformat_(nullptr),
     screen_(-1),
     renderer_id_(-1),
     safe_to_force_gpu_switch_(true) {
 }
 
 bool GLContextCGL::Initialize(GLSurface* compatible_surface,
-                              GpuPreference gpu_preference) {
+                              const GLContextAttribs& attribs) {

[piman, 2016/11/07 21:01:01]

Here and other context types: I think we should fail Initialize() if we request
features that are not available (!bind_generates_resources,
webgl_compatibility_context). Otherwise it could lead to confusion and bugs.

[Geoff Lang, 2016/11/07 21:36:21]

Done, I used a DCHECK but can change it to a failure if needed.

   DCHECK(compatible_surface);
 
-  gpu_preference = ui::GpuSwitchingManager::GetInstance()->AdjustGpuPreference(
-      gpu_preference);
+  GpuPreference gpu_preference =
+      ui::GpuSwitchingManager::GetInstance()->AdjustGpuPreference(
+          attribs.gpu_preference);
 
   GLContextCGL* share_context = share_group() ?
       static_cast<GLContextCGL*>(share_group()->GetContext()) : nullptr;
 
   CGLPixelFormatObj format = GetPixelFormat();
   if (!format)
     return false;
 
   // If using the discrete gpu, create a pixel format requiring it before we
   // create the context.
@@ skipping 172 matching lines @@
 
 GLContextCGL::~GLContextCGL() {
   Destroy();
 }
 
 GpuPreference GLContextCGL::GetGpuPreference() {
   return gpu_preference_;
 }
 
 }  // namespace gl