Yes, economic growth is enough to keep down feelings of discontent among Chinese, because they are happy with their new wealth. With the economic growth that has come to China, they are doing better than ever before. If their economy is happy, the people are happy too. Their discontent is at a minimum.
The reason why economic growth isn't enough to keep down feelings of discontent among the Chinese is because they are still living in mostly squalor as the government rakes in profits. Sure, their GDP is increasing, but the living conditions really aren't. It should make them even angrier and more discontent.
Economic growth is not enough to keep down feelings of discontent among the Chinese. Although economic growth will enable the average Chinese person to enjoy a higher level of income, they may still feel discontent based on things like government censorship of information, and pollution, which is a great problem in China. Smog is a very large issue in China, affecting the health of many of its citizens.
One aspect of economic growth for China is that just as in any other growing nation, the benefits are not spread equally. Therefore even if there is growth, this does not quell everybody because certain people are left out. Aside from that, there comes a point when even money won't make up for certain problems.
I could not imagine what it would take to manage an infrastructure for 1.35 billion people. But I do believe no matter how much economic growth you have there will always be those that feel they deserve more. More hours, more money, more benefits. even a small percent of that many people is a large group.