gpu: Add EGL fence support.

ui/gl/gl_surface_egl.h

 // 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.
 
 #ifndef UI_GL_GL_SURFACE_EGL_H_
 #define UI_GL_GL_SURFACE_EGL_H_
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
@@ skipping 49 matching lines @@
   virtual bool Initialize() OVERRIDE;
   virtual void Destroy() OVERRIDE;
   virtual bool Resize(const gfx::Size& size) OVERRIDE;
   virtual bool IsOffscreen() OVERRIDE;
   virtual bool SwapBuffers() OVERRIDE;
   virtual gfx::Size GetSize() OVERRIDE;
   virtual EGLSurface GetHandle() OVERRIDE;
   virtual std::string GetExtensions() OVERRIDE;
   virtual bool PostSubBuffer(int x, int y, int width, int height) OVERRIDE;
   virtual VSyncProvider* GetVSyncProvider() OVERRIDE;
+  virtual void SetMaximumFrameLatency(unsigned int frames) OVERRIDE;

[Sami, 2013/04/24 10:44:18]

We spoke with Daniel that maybe something like SetMaximumPendingSwaps would be a
better name for this since that's also used elsewhere in the code and the
current name sounds like this gives a hard guarantee when it doesn't really know
what's happening downstream.

[no sievers, 2013/04/24 12:23:53]

In gles2_implementation.cc we call it 'MaxSwapBuffers'.  

[epennerAtGoogle, 2013/04/24 19:33:38]

Okay. I stole this name from D3D :P  I'll rename.

 
  protected:
   virtual ~NativeViewGLSurfaceEGL();
   void SetHandle(EGLSurface surface);
 
  private:
   gfx::AcceleratedWidget window_;
   EGLSurface surface_;
   bool supports_post_sub_buffer_;
   EGLConfig config_;
 
+  std::deque<EGLSyncKHR> frame_fences_;
+  unsigned int max_frame_latency_;
+
   scoped_ptr<VSyncProvider> vsync_provider_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeViewGLSurfaceEGL);
 };
 
 // Encapsulates a pbuffer EGL surface.
 class GL_EXPORT PbufferGLSurfaceEGL : public GLSurfaceEGL {
  public:
   PbufferGLSurfaceEGL(bool software, const gfx::Size& size);
 
@@ skipping 14 matching lines @@
  private:
   gfx::Size size_;
   EGLSurface surface_;
 
   DISALLOW_COPY_AND_ASSIGN(PbufferGLSurfaceEGL);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_GL_SURFACE_EGL_H_