Revert 170550 - Revert 170477 - Removes the |event| parameter from ActivationDelegate::ShouldActiva…

Revert 170550 - Revert 170477 - Removes the |event| parameter from ActivationDelegate::ShouldActivate and makes the method const.

It is mostly unused, except for one place in RenderWidgetHostViewAura, where depending on the event type etc it will have a consequence. I think it's bad for a method with a const-sounding name like "ShouldActivate" to have side-effects.

Instead, I made the RWHVA store the data that would indicate a pointer activate and check that state during OnActivated(). It'd be a little cleaner if OnActivated had some way of knowing what the currently processed input event was, hence the TODO.

http://crbug.com/162100
R=sadrul@chromium.org
Review URL: https://codereview.chromium.org/11419251

TBR=ben@chromium.org
Review URL: https://codereview.chromium.org/11416292

TBR=ben@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=170571