ash: Record some additional information about the gestures.

ash: Record some additional information about the gestures.

Notable changes:
 * Expose GestureEventDetails::touch_points for all kinds of gestures (instead of just BEGIN/END). This makes it possible to count when 3-finger swipes vs 4/4-finger swipes separately.
 * Instead of using poorly-defined param_first/param_second when constructing a GestureEvent, use better-defined GestureEventDetails.

BUG=121179
TEST=covered by existing tests

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=147855

[sky, 2012-07-21 00:01:54]

http://codereview.chromium.org/10816008/diff/11002/ash/touch/touch_uma.cc
File ash/touch/touch_uma.cc (right):

http://codereview.chromium.org/10816008/diff/11002/ash/touch/touch_uma.cc#new...
ash/touch/touch_uma.cc:213: UMA_HISTOGRAM_ENUMERATION("Ash.GestureCreated",
Why are these histograms and not UserMetricsAction?

http://codereview.chromium.org/10816008/diff/11002/ui/base/gestures/gesture_s...
File ui/base/gestures/gesture_sequence.h (right):

http://codereview.chromium.org/10816008/diff/11002/ui/base/gestures/gesture_s...
ui/base/gestures/gesture_sequence.h:81: GestureEvent*
CreateGestureEvent(GestureEventDetails details,
const GestureEventDetails& (make a copy in the implementation). Update the
description too, since it makes it sound like it updates the value the caller
provided, but that isn't the case.

http://codereview.chromium.org/10816008/diff/11002/ui/base/gestures/gesture_t...
File ui/base/gestures/gesture_types.h (right):

http://codereview.chromium.org/10816008/diff/11002/ui/base/gestures/gesture_t...
ui/base/gestures/gesture_types.h:120: int touch_points_;  // Number of active
touch points in the gesture.
Add to initializer.

[sadrul, 2012-07-21 00:55:40]

http://codereview.chromium.org/10816008/diff/11002/ash/touch/touch_uma.cc
File ash/touch/touch_uma.cc (right):

http://codereview.chromium.org/10816008/diff/11002/ash/touch/touch_uma.cc#new...
ash/touch/touch_uma.cc:213: UMA_HISTOGRAM_ENUMERATION("Ash.GestureCreated",
On 2012/07/21 00:01:54, sky wrote:
> Why are these histograms and not UserMetricsAction?

We considered using UserMetricsAction, but since we would also be doing
comparisons between the different kinds of gestures created, we decided using
histograms instead. (the UserMetricsAction also brings in content/ dependency,
but that's perhaps a lesser issue)

http://codereview.chromium.org/10816008/diff/11002/ui/base/gestures/gesture_s...
File ui/base/gestures/gesture_sequence.h (right):

http://codereview.chromium.org/10816008/diff/11002/ui/base/gestures/gesture_s...
ui/base/gestures/gesture_sequence.h:81: GestureEvent*
CreateGestureEvent(GestureEventDetails details,
On 2012/07/21 00:01:54, sky wrote:
> const GestureEventDetails& (make a copy in the implementation). Update the
> description too, since it makes it sound like it updates the value the caller
> provided, but that isn't the case.

Done.

http://codereview.chromium.org/10816008/diff/11002/ui/base/gestures/gesture_t...
File ui/base/gestures/gesture_types.h (right):

http://codereview.chromium.org/10816008/diff/11002/ui/base/gestures/gesture_t...
ui/base/gestures/gesture_types.h:120: int touch_points_;  // Number of active
touch points in the gesture.
On 2012/07/21 00:01:54, sky wrote:
> Add to initializer.

Good catch! Done.

[sky, 2012-07-23 15:36:39]

LGTM