viz: Remove unnecessary fb != 0 check in bufferqueue

In BufferQueue::CopyBufferDamage DCHECK that a framebuffer is generated
instead of ignoring that generation might fail and then avoid deleting it.

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel
Change-Id: I75dcf48a444a613df0a653d3bc5d420afa416430
Reviewed-on: https://chromium-review.googlesource.com/c/1293796Reviewed-by: Yuri Wiitala <miu@chromium.org>
Commit-Queue: Daniele Castagna <dcastagna@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601714}

components/viz/service/display_embedder/buffer_queue.cc

@@ -75,6 +75,7 @@ void BufferQueue::CopyBufferDamage(int texture,
 
   GLuint dst_framebuffer = 0;
   gl_->GenFramebuffers(1, &dst_framebuffer);
+  DCHECK(dst_framebuffer);
   gl_->BindFramebuffer(GL_FRAMEBUFFER, dst_framebuffer);
   gl_->BindTexture(texture_target_, texture);
   gl_->FramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
@@ -86,7 +87,6 @@ void BufferQueue::CopyBufferDamage(int texture,
   }
   gl_->BindTexture(texture_target_, 0);
   gl_->Flush();
-  if (dst_framebuffer != 0)
   gl_->DeleteFramebuffers(1, &dst_framebuffer);
 }