Allow putting NV12 software GMBs into overlays on windows

ui/gl/gl_image_memory.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.
 
 #ifndef UI_GL_GL_IMAGE_MEMORY_H_
 #define UI_GL_GL_IMAGE_MEMORY_H_
 
 #include "ui/gl/gl_image.h"
 
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "base/numerics/safe_math.h"
 #include "ui/gfx/buffer_types.h"
 #include "ui/gl/gl_export.h"
 
 namespace gl {
 
 class GL_EXPORT GLImageMemory : public GLImage {
  public:
   GLImageMemory(const gfx::Size& size, unsigned internalformat);
 
   bool Initialize(const unsigned char* memory,
                   gfx::BufferFormat format,
                   size_t stride);
 
+  // Safe downcast. Returns |nullptr| on failure.
+  static GLImageMemory* FromGLImage(GLImage* image);
+
   // Overridden from GLImage:
   gfx::Size GetSize() override;
   unsigned GetInternalFormat() override;
   bool BindTexImage(unsigned target) override;
   void ReleaseTexImage(unsigned target) override {}
   bool CopyTexImage(unsigned target) override;
   bool CopyTexSubImage(unsigned target,
                        const gfx::Point& offset,
                        const gfx::Rect& rect) override;
   bool ScheduleOverlayPlane(gfx::AcceleratedWidget widget,
                             int z_order,
                             gfx::OverlayTransform transform,
                             const gfx::Rect& bounds_rect,
                             const gfx::RectF& crop_rect) override;
   void Flush() override {}
+  Type GetType() const override;
 
   static unsigned GetInternalFormatForTesting(gfx::BufferFormat format);
 
+  const unsigned char* memory() { return memory_; }
+  size_t stride() const { return stride_; }
+  gfx::BufferFormat format() const { return format_; }
+
  protected:
   ~GLImageMemory() override;
 
-  gfx::BufferFormat format() const { return format_; }
-  size_t stride() const { return stride_; }
-
  private:
   const gfx::Size size_;
   const unsigned internalformat_;
   const unsigned char* memory_;
   gfx::BufferFormat format_;
   size_t stride_;
 
   DISALLOW_COPY_AND_ASSIGN(GLImageMemory);
 };
 
 }  // namespace gl
 
 #endif  // UI_GL_GL_IMAGE_MEMORY_H_