Add a glBegin/End pair to make glBindFramebuffer work

content/common/gpu/image_transport_surface_fbo_mac.mm

 // 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 "content/common/gpu/image_transport_surface_fbo_mac.h"
 
 #include "content/common/gpu/gpu_messages.h"
 #include "content/common/gpu/image_transport_surface_calayer_mac.h"
 #include "content/common/gpu/image_transport_surface_iosurface_mac.h"
 #include "ui/base/cocoa/remote_layer_api.h"
@@ skipping 63 matching lines @@
 
   if (made_current_)
     return true;
 
   AllocateOrResizeFramebuffer(gfx::Size(1, 1), 1.f);
 
   made_current_ = true;
   return true;
 }
 
+void ImageTransportSurfaceFBO::NotifyWasBound() {
+  // Sometimes calling glBindFramebuffer doesn't seem to be enough to get
+  // rendered contents to show up in the color attachment. It appears that doing
+  // a glBegin/End pair with program 0 is enough to tickle the driver into
+  // actually effecting the binding.
+  // http://crbug.com/435786
+  DCHECK(has_complete_framebuffer_);
+
+  // We will restore the current program after the dummy glBegin/End pair.
+  // Ensure that we will be able to restore this state before attempting to
+  // change it.
+  GLint old_program_signed = 0;
+  glGetIntegerv(GL_CURRENT_PROGRAM, &old_program_signed);
+  GLuint old_program = static_cast<GLuint>(old_program_signed);
+  if (old_program && glIsProgram(old_program)) {
+    // A deleted program cannot be re-bound.
+    GLint delete_status = GL_FALSE;
+    glGetProgramiv(old_program, GL_DELETE_STATUS, &delete_status);
+    if (delete_status == GL_TRUE)
+      return;
+    // A program which has had the most recent link fail cannot be re-bound.
+    GLint link_status = GL_FALSE;
+    glGetProgramiv(old_program, GL_LINK_STATUS, &link_status);
+    if (link_status != GL_TRUE)
+      return;
+  }
+
+  // Issue the dummy call and then restore the state.
+  glUseProgram(0);
+  GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
+  DCHECK(status == GL_FRAMEBUFFER_COMPLETE);
+  glBegin(GL_TRIANGLES);
+  glEnd();
+  glUseProgram(old_program);
+}
+
 unsigned int ImageTransportSurfaceFBO::GetBackingFrameBufferObject() {
   return fbo_id_;
 }
 
 bool ImageTransportSurfaceFBO::SetBackbufferAllocation(bool allocation) {
   if (backbuffer_suggested_allocation_ == allocation)
     return true;
   backbuffer_suggested_allocation_ = allocation;
   AdjustBufferAllocation();
   if (!allocation)
@@ skipping 231 matching lines @@
     return;
   }
 
   has_complete_framebuffer_ = true;
 
   glBindTexture(GL_TEXTURE_RECTANGLE_ARB, previous_texture_id);
   // The FBO remains bound for this GL context.
 }
 
 }  // namespace content