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 18bc5ff5fd6894a118e14d0a33cfeb9167408355..b788b6a5a2cc921c44f7bf7ebd971ddbb7c71829 100644
--- a/gpu/perftests/texture_upload_perftest.cc
+++ b/gpu/perftests/texture_upload_perftest.cc
@@ -122,10 +122,10 @@ class TextureUploadPerfTest : public testing::Test {
 
     glViewport(0, 0, size_.width(), size_.height());
 
-    if (gpu_timing_.Initialize(gl_context_.get())) {
+    gpu_timing_.Initialize(gl_context_.get());
+    if (gpu_timing_.GetTimerType() != GPUTiming::kTimerTypeInvalid) {
       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";