1. A method, implemented at least in part by a computing device comprising a display and a graphics processing unit (GPU), for rendering content for display using a plurality of rendering contexts, the method comprising: for a lower priority rendering context of the plurality of rendering contexts: receiving, from a first software component associated with the lower priority rendering context, a plurality of requests to render blocks of content on the display using the GPU, the blocks of content for the lower priority rendering context having a pre-determined block size, and the plurality of requests to render blocks of content for the lower priority rendering context being limited to a pre-determined number of requests in a queue for the GPU at a time: wherein each request is for rendering a specific block of content; wherein the first software component is a GPU-based renderer and is responsible for rendering background content, the background content being content other than user interface elements; and wherein a lower priority is applied to the plurality of requests to render content for the lower priority rendering context; for a higher priority rendering context of the plurality of rendering contexts: receiving, from a second software component associated with the higher priority rendering context, a plurality of requests to render content on the display using the GPU, the requests to render content for the higher priority rendering context not having the pre-determined block size, and the plurality of requests to render content for the higher priority rendering context not being limited to the pre-determined number of requests in the queue for the GPU at a time; wherein the second software component is responsible for drawing user interface elements on the display and for receiving user interface input from a user of the computing device; and wherein a higher priority is applied to the plurality of requests received for the higher priority rendering context; and displaying content on the display of the computing device according to the plurality of requests received for the lower priority rendering context and the plurality of requests received for the higher priority rendering context.