Fixed warning from Core Graphics related to zero-width or zero-height

ui/gfx/surface/accelerated_surface_mac.h

 // Copyright (c) 2011 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 UI_GFX_SURFACE_ACCELERATED_SURFACE_MAC_H_
 #define UI_GFX_SURFACE_ACCELERATED_SURFACE_MAC_H_
 #pragma once
 
 #include <CoreFoundation/CoreFoundation.h>
 
@@ skipping 106 matching lines @@
   // |target| is the target type for the color buffer.
   void AllocateRenderBuffers(GLenum target, const gfx::Size& size);
 
   // Helper function to attach the buffers previously allocated by a call to
   // AllocateRenderBuffers().  On return, |fbo_| can be used for
   // rendering.  |target| must be the same value as used in the call to
   // AllocateRenderBuffers().  Returns |true| if the resulting framebuffer
   // object is valid.
   bool SetupFrameBufferObject(GLenum target);
 
+  gfx::Size ClampToValidDimensions(const gfx::Size& size);
+
   // The OpenGL context, and pbuffer drawable, used to transfer data
   // to the shared region (IOSurface or TransportDIB). Strictly
   // speaking, we do not need to allocate a GL context all of the
   // time. We only need one if (a) we are using the IOSurface code
   // path, or (b) if we are allocating an FBO internally.
   scoped_refptr<gfx::GLSurface> gl_surface_;
   scoped_refptr<gfx::GLContext> gl_context_;
   // Either |io_surface_| or |transport_dib_| is a valid pointer, but not both.
   // |io_surface_| is non-NULL if the IOSurface APIs are supported (Mac OS X
   // 10.6 and later).
   // TODO(dspringer,kbr): Should the GPU backing store be encapsulated in its
   // own class so all this implementation detail is hidden?
   base::mac::ScopedCFTypeRef<CFTypeRef> io_surface_;
 
   // The id of |io_surface_| or 0 if that's NULL.
   uint64 io_surface_id_;
 
   // TODO(dspringer): If we end up keeping this TransportDIB mechanism, this
   // should really be a scoped_ptr_malloc<>, with a deallocate functor that
   // runs |dib_free_callback_|.  I was not able to figure out how to
   // make this work (or even compile).
   scoped_ptr<TransportDIB> transport_dib_;
   gfx::Size surface_size_;
+  // It's important to avoid allocating zero-width or zero-height
+  // IOSurfaces and textures on the Mac, so we clamp each to a minimum
+  // of 1. This is the real size of the surface; surface_size_ is what
+  // the user requested.
+  gfx::Size real_surface_size_;
   // TODO(kbr): the FBO management should not be in this class at all.
   // However, if it is factored out, care needs to be taken to not
   // introduce another copy of the color data on the GPU; the direct
   // binding of the internal texture to the IOSurface saves a copy.
   bool allocate_fbo_;
   // If the IOSurface code path is being used, then this texture
   // object is always allocated. Otherwise, it is only allocated if
   // the user requests an FBO be allocated.
   GLuint texture_;
   // The FBO and renderbuffer are only allocated if allocate_fbo_ is
   // true.
   GLuint fbo_;
   GLuint depth_stencil_renderbuffer_;
   // Allocate a TransportDIB in the renderer.
   scoped_ptr<Callback2<size_t, TransportDIB::Handle*>::Type>
       dib_alloc_callback_;
   scoped_ptr<Callback1<TransportDIB::Id>::Type> dib_free_callback_;
 };
 
 #endif  // UI_GFX_SURFACE_ACCELERATED_SURFACE_MAC_H_