Mac/gpu: Don't show uninitialized surfaces while resizing plugins / composited tabs.

app/surface/io_surface_support_mac.h

 // Copyright (c) 2010 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.
 
 #ifndef APP_SURFACE_IO_SURFACE_SUPPORT_MAC_H_
 #define APP_SURFACE_IO_SURFACE_SUPPORT_MAC_H_
 #pragma once
 
 #include <CoreFoundation/CoreFoundation.h>
 #include <mach/mach.h>
@@ skipping 28 matching lines @@
   virtual uint32 IOSurfaceGetID(CFTypeRef io_surface) = 0;
   virtual CFTypeRef IOSurfaceLookup(uint32 io_surface_id) = 0;
 
   // The following two APIs are more robust and secure, but
   // unfortunately it looks like it will be a lot of work to correctly
   // transmit a mach port from process to process (possibly requiring
   // a side channel for or extension of the Chrome IPC mechanism)
   virtual mach_port_t IOSurfaceCreateMachPort(CFTypeRef io_surface) = 0;
   virtual CFTypeRef IOSurfaceLookupFromMachPort(mach_port_t port) = 0;
 
+  virtual size_t IOSurfaceGetWidth(CFTypeRef io_surface) = 0;
+  virtual size_t IOSurfaceGetHeight(CFTypeRef io_surface) = 0;
+
   virtual CGLError CGLTexImageIOSurface2D(CGLContextObj ctx,
                                           GLenum target,
                                           GLenum internal_format,
                                           GLsizei width,
                                           GLsizei height,
                                           GLenum format,
                                           GLenum type,
                                           CFTypeRef io_surface,
                                           GLuint plane) = 0;
 
  protected:
   IOSurfaceSupport();
   virtual ~IOSurfaceSupport();
 
   DISALLOW_COPY_AND_ASSIGN(IOSurfaceSupport);
 };
 
 #endif  // APP_SURFACE_IO_SURFACE_SUPPORT_MAC_H_