Make surface GetFormat pure virtual, add missing overrides.

ui/gl/gl_surface_wgl.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_surface_wgl.h"
 
 #include <memory>
 
 #include "base/logging.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 302 matching lines @@
   RECT rect;
   BOOL result = GetClientRect(child_window_, &rect);
   DCHECK(result);
   return gfx::Size(rect.right - rect.left, rect.bottom - rect.top);
 }
 
 void* NativeViewGLSurfaceWGL::GetHandle() {
   return device_context_;
 }
 
+GLSurfaceFormat NativeViewGLSurfaceWGL::GetFormat() {
+  return GLSurfaceFormat();
+}
+
 PbufferGLSurfaceWGL::PbufferGLSurfaceWGL(const gfx::Size& size)
     : size_(size),
       device_context_(NULL),
       pbuffer_(NULL) {
   // Some implementations of Pbuffer do not support having a 0 size. For such
   // cases use a (1, 1) surface.
   if (size_.GetArea() == 0)
     size_.SetSize(1, 1);
 }
 
@@ skipping 54 matching lines @@
 }
 
 gfx::Size PbufferGLSurfaceWGL::GetSize() {
   return size_;
 }
 
 void* PbufferGLSurfaceWGL::GetHandle() {
   return device_context_;
 }
 
+GLSurfaceFormat PbufferGLSurfaceWGL::GetFormat() {
+  return GLSurfaceFormat();
+}
+
 }  // namespace gl