33b7de85b6
Bug 5763685 Long text in a ScrollView (not when the View's internal scroll is used) is cached as a unique display list when hardware rendering is on. As a result, each time the text is edited, the entire display list has to be updated, which takes a significant amount of time (up to 500ms for a few thousand lines), proportional to the size of the text. This CL splits the text into multiple display lists as the text is edited. The boundaries of the display list are aligned with paragraphs. There is still an issue when the number of lines changes: onLayout() is called which invalidates all the display list. When the source of that change is line wrapping and not a change in the view's dimensions, we should be able to simply shift down the previous DL instead of re-creating everything. Change-Id: I7de49a1e5637cdfc9ef06b64b1ec4b61d9ea2415