Disable GPU-GPU video uploads for R8UI textures.

R=kbr@chromium.org

BUG=710673

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: I323c5c020f62e4d388a5cae547b93887fc375640
Reviewed-on: https://chromium-review.googlesource.com/581348Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488713}

third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp

@@ -4879,6 +4879,11 @@ bool WebGLRenderingContextBase::CanUseTexImageByGPU(GLenum format,
     return false;
 #endif
 
+  // TODO(kbr): continued bugs are seen on Linux with AMD's drivers handling
+  // uploads to R8UI textures. crbug.com/710673
+  if (format == GL_RED_INTEGER)
+    return false;
+
 #if defined(OS_ANDROID)
   // TODO(kbr): bugs were seen on Android devices with NVIDIA GPUs
   // when copying hardware-accelerated video textures to