Fix offscreen rendering on iOS by not assuming that the default window bound framebuffer is 0

ui/gl/gl_surface_ios.h

 // Copyright 2014 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.h"
 
 namespace gfx {
 
 class GL_EXPORT GLSurfaceIOS : public GLSurface {
  public:
   GLSurfaceIOS(gfx::AcceleratedWidget widget,
                const gfx::SurfaceConfiguration requested_configuration);
 
   bool SwapBuffers() override;
   void Destroy() override;
   bool IsOffscreen() override;
   gfx::Size GetSize() override;
   void* GetHandle() override;
   bool OnMakeCurrent(GLContext* context) override;
+  unsigned int GetBackingFrameBufferObject() override;

[iansf, 2015/06/16 01:21:27]

Is there a corresponding change in gl_surface.h that should be included?

unsigned int GetBackingFramebufferObject() { return 0; }

or something like that?

Also, the 'b' in GetBackingFramebufferObject should be lowercase, not uppercase.

 
  private:
   gfx::AcceleratedWidget widget_;
   uint32_t framebuffer_;
   uint32_t colorbuffer_;
   uint32_t depthbuffer_;
   uint32_t stencilbuffer_;
   uint32_t depth_stencil_packed_buffer_;
   Size last_configured_size_;
   bool framebuffer_setup_complete_;
   void SetupFramebufferIfNecessary();
 
   DISALLOW_COPY_AND_ASSIGN(GLSurfaceIOS);
 };
 
 }  // namespace gfx