[Contextual Search] Pinch zoom might cause a crash.

[Contextual Search] Pinch zoom might cause a crash.

ContextualSearchEventFilter has a complex logic to detect
where to propagate events to, whether the Search Panel or
the Search Content View. Besides that, a single stream of
events (a single gesture) might be forwarded to different
targets depending on a number of factors (whether the
Panel was maximized, whether the gesture was horizontal
or vertical, whether the Search Content View is scrolled
at the top, and so on).

Things can get much more complicated when multiple
pointers are involved, like in gestures with multiple
fingers. If we mess with the order of the events, or
don't properly forward events from all pointers to the
Search Content View it will crash.

This CL fixes the problem by:

1) Forwarding all pointer events when multiple finger
gestures are used.

2) Ignoring multitouch events when forwarding horizontal
gestures to the expanded Panel. In this particular case,
we must ignore multitouch events because the presence of
a second pointer will cause the Search Page to scroll,
which is not supposed to happen in this case. So, now
we are properly ignoring ACTION_POINTER_DOWN and
ACTION_POINTER_UP events, while at the same time,
creating MotionEvents with a single pointer in order
to implement the intended "lock horizontally" behavior.

BUG=485008
BUG=486901
BUG=486902
Committed: https://crrev.com/ffea7a5b91079deae044398bc7b01e22275d868e
Cr-Commit-Position: refs/heads/master@{#329275}

[pedro (no code reviews), 2015-05-11 21:29:38]

pedrosimonetti@chromium.org changed reviewers:
+ donnd@chromium.org, dtrainor@chromium.org

[pedro (no code reviews), 2015-05-11 21:29:57]

Hey guys. Please take a look at this change.

[David Trainor- moved to gerrit, 2015-05-11 22:05:35]

lgtm

https://codereview.chromium.org/1137003003/diff/1/chrome/android/java/src/org...
File
chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/eventfilter/ContextualSearchEventFilter.java
(right):

https://codereview.chromium.org/1137003003/diff/1/chrome/android/java/src/org...
chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/eventfilter/ContextualSearchEventFilter.java:399:
private MotionEvent lockEventHorizontallty(MotionEvent e, float y) {
Horizontallty -> Horizontally

Should we assert that there is only one touch going on here, or are we okay if
there is more than one?

[pedro (no code reviews), 2015-05-11 22:55:03]

Thanks David!

https://codereview.chromium.org/1137003003/diff/1/chrome/android/java/src/org...
File
chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/eventfilter/ContextualSearchEventFilter.java
(right):

https://codereview.chromium.org/1137003003/diff/1/chrome/android/java/src/org...
chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/eventfilter/ContextualSearchEventFilter.java:399:
private MotionEvent lockEventHorizontallty(MotionEvent e, float y) {
On 2015/05/11 22:05:34, David Trainor wrote:
> Horizontallty -> Horizontally
> 
> Should we assert that there is only one touch going on here, or are we okay if
> there is more than one?

As we discussed in person, I removed that method (code is now inline, to prevent
other from misusing it), changed to use getActionMasked() and added comments to
clarify what we are doing here.

[pedro (no code reviews), 2015-05-11 22:57:15]

The CQ bit was checked by pedrosimonetti@chromium.org

[pedro (no code reviews), 2015-05-11 22:57:15]

The patchset sent to the CQ was uploaded after l-g-t-m from
dtrainor@chromium.org
Link to the patchset: https://codereview.chromium.org/1137003003/#ps20001
(title: "Addressing David's comment")

[commit-bot: I haz the power, 2015-05-11 22:59:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1137003003/20001

[commit-bot: I haz the power, 2015-05-11 23:45:04]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-05-11 23:46:42]

Patchset 2 (id:??) landed as
https://crrev.com/ffea7a5b91079deae044398bc7b01e22275d868e
Cr-Commit-Position: refs/heads/master@{#329275}