gpu: Fix some context lost marking glitches+leaks and add UMA stats

ui/gl/gl_context_stub_with_extensions.cc

Index: ui/gl/gl_context_stub_with_extensions.cc
diff --git a/ui/gl/gl_context_stub_with_extensions.cc b/ui/gl/gl_context_stub_with_extensions.cc
index 1065df789fb226aa3c9594b2a21d90180a4f5e8c..855eaa2a275d7bde54942fba3c469b4c37eae3d8 100644
--- a/ui/gl/gl_context_stub_with_extensions.cc
+++ b/ui/gl/gl_context_stub_with_extensions.cc
@@ -27,4 +27,10 @@ std::string GLContextStubWithExtensions::GetGLVersion() {
   return version_str_;
 }
 
+bool GLContextStubWithExtensions::WasAllocatedUsingRobustnessExtension() {
+  return HasExtension("GL_ARB_robustness") ||
+         HasExtension("GL_KHR_robustness") ||
+         HasExtension("GL_EXT_robustness");
+}
+
 }  // namespace gfx