Harrington Investments is locked in a battle with PepsiCo and Coca-Cola that would require the soda giants to be more transparent about the impact their sugary drinks have on public health. Now, it just needs to hope that enough of its fellow shareholders agree. The small California investment firm is asking shareholders to vote on a measure requiring PepsiCo and Coca-Cola to provide the information through an independent report, with a focus on beverages marketed to children and young consumers. "We have to put continued pressure and chip away at them and show that we're not going away. This issue isn't going away," said Brianna Harrington, a research analyst and shareholder advocacy coordinator at Harrington Investments. "It's only going to become more and more relevant. It's only going to become more serious."