Plumb through EGL_NV_post_sub_buffer and GLX_MESA_copy_sub_buffer.

ui/gfx/gl/gl_surface_egl.cc

Index: ui/gfx/gl/gl_surface_egl.cc
diff --git a/ui/gfx/gl/gl_surface_egl.cc b/ui/gfx/gl/gl_surface_egl.cc
index 6f6d630fc7ba1611a6efe8d50ab0375487eae049..11601299792963df8ede162bcda2ae6bb39dab89 100644
--- a/ui/gfx/gl/gl_surface_egl.cc
+++ b/ui/gfx/gl/gl_surface_egl.cc
@@ -173,7 +173,8 @@ EGLNativeDisplayType GLSurfaceEGL::GetNativeDisplay() {
 NativeViewGLSurfaceEGL::NativeViewGLSurfaceEGL(bool software,
                                                gfx::PluginWindowHandle window)
     : window_(window),
-      surface_(NULL)
+      surface_(NULL),
+      supports_post_sub_buffer_(false)
 {
   software_ = software;
 }
@@ -190,11 +191,18 @@ bool NativeViewGLSurfaceEGL::Initialize() {
     return false;
   }
 
+  static const EGLint egl_window_attributes_sub_buffer[] = {
+    EGL_POST_SUB_BUFFER_SUPPORTED_NV, EGL_TRUE,
+    EGL_NONE
+  };
+
   // Create a surface for the native window.
   surface_ = eglCreateWindowSurface(GetDisplay(),
                                     GetConfig(),
                                     window_,
-                                    NULL);
+                                    gfx::g_EGL_NV_post_sub_buffer ?
+                                      egl_window_attributes_sub_buffer :
+                                      NULL);
 
   if (!surface_) {
     LOG(ERROR) << "eglCreateWindowSurface failed with error "
@@ -203,6 +211,13 @@ bool NativeViewGLSurfaceEGL::Initialize() {
     return false;
   }
 
+  EGLint surfaceVal;
+  EGLBoolean retVal = eglQuerySurface(GetDisplay(),

[apatrick_chromium, 2011/11/10 19:33:16]

Is it really the case that if you ask for a surface with EGL_NV_post_sub_buffer,
it will succeed but then report that it is not supported via QuerySurface? It
would be nice if the feature info code could just assume that if the
EGL_NV_post_sub_buffer extension is reported as available then  it can report it
as available to the client.

[jonathan.backer, 2011/11/10 21:00:25]

I think so. I was inspired by some ChromeOS WM code.

From the bottom of
http://www.khronos.org/registry/egl/extensions/NV/EGL_NV_post_sub_buffer.txt in
the revision history:

"Allowed EGL_POST_SUB_BUFFER_SUPPORTED_NV to be used as a hint when creating
window surfaces."

FWIW, the Intel GLES stack succeeds with the code as is (still get a window
surface), but correctly says that it doesn't support the extension.

+                                      surface_,
+                                      EGL_POST_SUB_BUFFER_SUPPORTED_NV,
+                                      &surfaceVal);
+  supports_post_sub_buffer_ = (surfaceVal && retVal) == EGL_TRUE;
+
   return true;
 }
 
@@ -247,6 +262,16 @@ EGLSurface NativeViewGLSurfaceEGL::GetHandle() {
   return surface_;
 }
 
+bool NativeViewGLSurfaceEGL::SupportsPostSubBuffer() {
+  return supports_post_sub_buffer_;
+}
+
+bool NativeViewGLSurfaceEGL::PostSubBuffer(
+    int x, int y, int width, int height) {
+  DCHECK(supports_post_sub_buffer_);
+  return eglPostSubBufferNV(GetDisplay(), surface_, x, y, width, height);
+}
+
 PbufferGLSurfaceEGL::PbufferGLSurfaceEGL(bool software, const gfx::Size& size)
     : size_(size),
       surface_(NULL) {