Implement Android accessible hit testing using an IPC to the renderer process.

Implement Android accessible hit testing using an IPC to the renderer process.

Only Blink can accurately determine what node is under the user's finger.
Implement this by sending a hit test request every time the user does
touch exploration, and returning a hover event on the appropriate accessible
node in response.

The test is meant to be a good sanity test and a skeleton, it tests that
the hit test request returns a hover event in response, and I intend to
follow this up with more specific tests of behavior as we tweak the
algorithm.

BUG=357371
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=272193

[dmazzoni, 2014-05-15 23:09:48]

+plundblad for a first look

[Peter Lundblad, 2014-05-19 16:58:44]

https://codereview.chromium.org/290633002/diff/20001/content/public/android/j...
File
content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java
(right):

https://codereview.chromium.org/290633002/diff/20001/content/public/android/j...
content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java:256:
nativeHitTest(mNativeObj, cssX, cssY);
Do we get lots of these events if a user just holds his finger
on the screen (you never hold your finger exactly still)?  Could the render
process
be flooded if that's the case?  Don't know if this actually is an issue, just
making sure it's been considered.

[dmazzoni, 2014-05-19 17:02:08]

On 2014/05/19 16:58:44, Peter Lundblad wrote:
>
https://codereview.chromium.org/290633002/diff/20001/content/public/android/j...
> File
>
content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java
> (right):
> 
>
https://codereview.chromium.org/290633002/diff/20001/content/public/android/j...
>
content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java:256:
> nativeHitTest(mNativeObj, cssX, cssY);
> Do we get lots of these events if a user just holds his finger
> on the screen (you never hold your finger exactly still)?  Could the render
> process
> be flooded if that's the case?  Don't know if this actually is an issue, just
> making sure it's been considered.

Yes, we get lots of these events, but we should be able to handle it. Remember
that every touch event would normally be sending an IPC to the render process if
touch exploration is off, that's normal.

[Peter Lundblad, 2014-05-19 18:38:00]

lgtm

Cool!

[dmazzoni, 2014-05-19 19:12:56]

+jam for content/

[dmazzoni, 2014-05-19 19:13:36]

+inferno for content/common/accessibility_messages*

[jam, 2014-05-20 04:31:14]

lgtm for files outside accessibility directories

https://codereview.chromium.org/290633002/diff/20001/content/browser/renderer...
File content/browser/renderer_host/render_widget_host_impl.cc (right):

https://codereview.chromium.org/290633002/diff/20001/content/browser/renderer...
content/browser/renderer_host/render_widget_host_impl.cc:2042: Send(new
AccessibilityMsg_HitTest(GetRoutingID(), point));
nit: routing_id_ (I know there are examples of the method, but we should change
them)

[Tom Sepez, 2014-05-20 16:19:03]

I can give you a "Messages LGTM" in place of inferno ... thanks.

[dmazzoni, 2014-05-20 18:30:57]

The CQ bit was checked by dmazzoni@chromium.org

[commit-bot: I haz the power, 2014-05-20 18:32:04]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dmazzoni@chromium.org/290633002/40001

[commit-bot: I haz the power, 2014-05-20 21:57:16]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  android_clang_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_clang_dbg/bui...)
  android_dbg_triggered_tests on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_dbg_triggered...)
  linux_chromium_chromeos_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_chrome...)
  linux_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_rel/bu...)
  mac_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_rel/buil...)
  win_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_rel/buil...)
  win_chromium_x64_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_x64_rel/...)

[dmazzoni, 2014-05-20 22:13:55]

The CQ bit was unchecked by dmazzoni@chromium.org

[dmazzoni, 2014-05-20 22:20:42]

The CQ bit was checked by dmazzoni@chromium.org

[commit-bot: I haz the power, 2014-05-20 22:22:28]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dmazzoni@chromium.org/290633002/60001

[dmazzoni, 2014-05-21 17:23:13]

The CQ bit was unchecked by dmazzoni@chromium.org

[dmazzoni, 2014-05-21 19:41:22]

The CQ bit was checked by dmazzoni@chromium.org

[commit-bot: I haz the power, 2014-05-21 19:57:19]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dmazzoni@chromium.org/290633002/100001

[commit-bot: I haz the power, 2014-05-22 01:43:44]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  android_clang_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_clang_dbg/bui...)
  android_dbg_triggered_tests on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_dbg_triggered...)

[commit-bot: I haz the power, 2014-05-22 04:31:02]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-05-22 04:31:02]

Try jobs failed on following builders:
  android_clang_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_clang_dbg/bui...)

[dmazzoni, 2014-05-22 05:54:47]

The CQ bit was checked by dmazzoni@chromium.org

[commit-bot: I haz the power, 2014-05-22 05:56:27]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dmazzoni@chromium.org/290633002/120001

[commit-bot: I haz the power, 2014-05-22 15:42:28]

Change committed as 272193