Bug 945105 patch 1:  Revert the changes to RestyleManager::ComputeStyleChangeFor from bug 898333, patch 2, since they cause skipping (in addition to the desired skipping) of continuations that do need restyling, in the case of directly restyling an element where continuations have different styles.  r=heycam
Bug 945105 patch 2:  Convert RestyleManager::ComputeStyleChangeFor from while loops to for loops to make it easier to add continue statements to it.  r=heycam
Bug 945105 patch 3:  Replace changes to ComputeStyleChangeFor with a check of GetPrevContinuationWithSameStyle to avoid the duplication in a way that still doesn't break direct restyling of an element whose continuations have different styles.  r=heycam
Bug 945105 patch 4:  Add reftest.  r=heycam

I confirmed that the test fails as expected without the patch, and
passes with the patch.