Handle CONTEXT LOST issue with Queries

gpu/command_buffer/client/gles2_implementation.h

Index: gpu/command_buffer/client/gles2_implementation.h
diff --git a/gpu/command_buffer/client/gles2_implementation.h b/gpu/command_buffer/client/gles2_implementation.h
index 9b07a32f43a7a0c96627dc819c2845fa01bb78fe..a5d5e6a7879468ae1d1d68c9d81cd8f7e165fd7a 100644
--- a/gpu/command_buffer/client/gles2_implementation.h
+++ b/gpu/command_buffer/client/gles2_implementation.h
@@ -477,6 +477,11 @@ class GLES2_IMPL_EXPORT GLES2Implementation {
 
   void FinishHelper();
 
+  // Checks if the context is lost.
+  // NOTE: This is an expensive call and should only be called
+  // for error checking.
+  bool MustBeContextLost();
+
   GLES2Util util_;
   GLES2CmdHelper* helper_;
   TransferBufferInterface* transfer_buffer_;
@@ -567,6 +572,8 @@ class GLES2_IMPL_EXPORT GLES2Implementation {
 
   ErrorMessageCallback* error_message_callback_;
 
+  bool context_lost_;
+
   DISALLOW_COPY_AND_ASSIGN(GLES2Implementation);
 };