What Algorithm is using in Chrome search?
You can find more information regarding the architecture here:http://www.chromium.org/developers/design-documents/find-bar
I will try to explain a more detailed response that will help you navigate through the Chromium source next time you need something more.
When a user initiates a find in Chromium, we basically register a notification to the observer for results. Every find call is asynchronous, and the results of the search is sent as a notification message by the renderer. This is handled in FindBarController::Observe
The first thing that happens when you press the next/previous/enter, FindBarView::ButtonPressed it tells the current Tab Contents to start finding TabContents::StartFinding. You will notice that in that piece of code it sends an asynchronous request to the IPC. You can view how we send it here: RendererViewHost::StartFinding
Since Chromium is a multi-process architecture, we send messages through the IPC message handler. You can view the link above to see how messages are being sent. The render hosts sends a message to the render view, RenderView::OnFind. From that point on, you know that the find logic is clearly in WebKit source code, not in Chromium. WebFrameImpl::find
Now in WebKit land, the logic where it finds the string is in Editor::findString and if you notice what the algorithm is, basically traversing DOM through a given range using WebKit/WebCore/editing/TextIterator.h The comments in WebKit are not that great in comparison to Chromium, but the quality of the Code is pretty high so you will have no problem reading 3000+ loc.
The reason why I am telling you all this is for your benefit, so if you want to know more about Chromium/WebKit, you know how to look through the source code :) I highly recommend http://dev.chromium.org/developers
Pure speculation, but quite likely that it tokenizes the page into words (with their associated ranges), then it puts those words into either a Radix Tree or a Trie and does a prefix search within the tree.