This is the G-Mail login logo. There is a rectangle which contains an "M" that uses the left and right of the rectangle to form the left and right of the "M". There is an arrow through the top that points down.
This Gmail Login icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 6,000 icons, all in the same style and quality.