Merge to M55: Use BrowserAccessibility::GetClosestPlatformObject consistently

Merge to M55: Use BrowserAccessibility::GetClosestPlatformObject consistently

We had two code blocks that were trying to do the same thing as
BrowserAccessibility::GetClosestPlatformObject(), but they should have
just called that function instead.

Also, the two code blocks had a bug in that they considered iframe elements
to be leaf nodes, which could cause problems. GetClosestPlatformObject()
doesn't have that bug because it only searches within the current frame,
so by switching to this function we fix that bug.

BUG=652805
Review-Url: https://codereview.chromium.org/2408843002
Cr-Commit-Position: refs/heads/master@{#424196}
(cherry picked from commit 6d2ed04992c82f83d1bbbd39520f3e1867b6b28c)

Committed: https://chromium.googlesource.com/chromium/src/+/ad7c976158eecc8bf288f1b2e5d1c19793e6630b

[dmazzoni, 2016-10-13 21:24:23]

Description was changed from

==========
Merge to M55: Use BrowserAccessibility::GetClosestPlatformObject consistently

We had two code blocks that were trying to do the same thing as
BrowserAccessibility::GetClosestPlatformObject(), but they should have
just called that function instead.

Also, the two code blocks had a bug in that they considered iframe elements
to be leaf nodes, which could cause problems. GetClosestPlatformObject()
doesn't have that bug because it only searches within the current frame,
so by switching to this function we fix that bug.

BUG=652805

Review-Url: https://codereview.chromium.org/2408843002
Cr-Commit-Position: refs/heads/master@{#424196}
(cherry picked from commit 6d2ed04992c82f83d1bbbd39520f3e1867b6b28c)
==========

to

==========
Merge to M55: Use BrowserAccessibility::GetClosestPlatformObject consistently

We had two code blocks that were trying to do the same thing as
BrowserAccessibility::GetClosestPlatformObject(), but they should have
just called that function instead.

Also, the two code blocks had a bug in that they considered iframe elements
to be leaf nodes, which could cause problems. GetClosestPlatformObject()
doesn't have that bug because it only searches within the current frame,
so by switching to this function we fix that bug.

BUG=652805

Review-Url: https://codereview.chromium.org/2408843002
Cr-Commit-Position: refs/heads/master@{#424196}
(cherry picked from commit 6d2ed04992c82f83d1bbbd39520f3e1867b6b28c)

Committed:
https://chromium.googlesource.com/chromium/src/+/ad7c976158eecc8bf288f1b2e5d1...
==========

[dmazzoni, 2016-10-13 21:24:24]

Committed patchset #1 (id:1) manually as
ad7c976158eecc8bf288f1b2e5d1c19793e6630b.