I don't think that is the primary reason. Indirectly, yes, but not in a direct way. Google wants people to use the web more, and it certainly looks like it will be very big in the future. There are two interesting features with Google Chrome: Improved navigation and improved Java Script execution.
Improved navigation (using the Omnibox as well as the new tab page), will make it easier for users to find what they want and have them stay longer, browsing the world.
It is not obvious why Google spend a lot of effort on improved Javascript execution speed. However, when you consider O3D, you get a hint what it is all about. O3D is a plugin that supports 3D graphics using the hardware acceleration of the graphic cards. This plugin use Javascript for execution, and if it will become a success, it is not acceptable with slow applications. The hope is that there will be more 3D games available online, where you don't have to install anything. You simply execute them on the web. If these games only work good enough on Google Chrome, guess what is going to happen? All other web browse suppliers will have to improve the Javascript engine execution. That way, Google wins even if people use other web browsers. That is, people stay more on the internet.
And then, Google Chrome pushes html 5, which will even further improve web browsing.
