Added disjoint context class which manages disjoints within gpu timing.

gpu/perftests/texture_upload_perftest.cc

Index: gpu/perftests/texture_upload_perftest.cc
diff --git a/gpu/perftests/texture_upload_perftest.cc b/gpu/perftests/texture_upload_perftest.cc
index 16dabb751450cad6207426d092367525b1f3d8d6..a2d870368116a6b0df31bece8f03d4921a9cb23b 100644
--- a/gpu/perftests/texture_upload_perftest.cc
+++ b/gpu/perftests/texture_upload_perftest.cc
@@ -123,7 +123,6 @@ class TextureUploadPerfTest : public testing::Test {
     if (gpu_timing_.Initialize(gl_context_.get())) {
       LOG(INFO) << "Gpu timing initialized with timer type: "
                 << gpu_timing_.GetTimerTypeName();
-      gpu_timing_.CheckAndResetTimerErrors();
       gpu_timing_.InvalidateTimerOffset();
     } else {
       LOG(WARNING) << "Can't initialize gpu timing";