Revert 158076 - Implement blacklist's force GPU capability in dual GPU machines.

ui/gl/gl_context_cgl.cc

Index: ui/gl/gl_context_cgl.cc
===================================================================
--- ui/gl/gl_context_cgl.cc	(revision 158210)
+++ ui/gl/gl_context_cgl.cc	(working copy)
@@ -13,7 +13,6 @@
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_surface_cgl.h"
-#include "ui/gl/gpu_switching_manager.h"
 
 namespace gfx {
 
@@ -28,9 +27,6 @@
                               GpuPreference gpu_preference) {
   DCHECK(compatible_surface);
 
-  gpu_preference = GpuSwitchingManager::GetInstance()->AdjustGpuPreference(
-      gpu_preference);
-
   GLContextCGL* share_context = share_group() ?
       static_cast<GLContextCGL*>(share_group()->GetContext()) : NULL;
 
@@ -220,6 +216,17 @@
   return gpu_preference_;
 }
 
+void GLContextCGL::ForceUseOfDiscreteGPU() {
+  static CGLPixelFormatObj format = NULL;
+  if (format)
+    return;
+  CGLPixelFormatAttribute attribs[1];
+  attribs[0] = static_cast<CGLPixelFormatAttribute>(0);
+  GLint num_pixel_formats = 0;
+  CGLChoosePixelFormat(attribs, &format, &num_pixel_formats);
+  // format is deliberately leaked.
+}
+
 void ScopedCGLDestroyRendererInfo::operator()(CGLRendererInfoObj x) const {
   CGLDestroyRendererInfo(x);
 }