Avoid rotation anchor during transitional fullscreen states.

Avoid rotation anchor during transitional fullscreen states.

FullscreenController::isFullscreen is called exclusively by
WebViewImpl::resizeWithBrowserControls to exclude use of rotation
anchor.  The reason is that anchors incorrectly interpret the initial
offset restoration in FullscreenController::didUpdateLayout as a
layout-induced change.  Rotation anchors in particular tend to
snap page scale factor to extreme values as a result.

During the observed case, fullscreen state is still NeedsScrollAndStateRestore.
It's reasonable to consider every state in the machine other than "Initial"
(non-fullscreen) to count as fullscreen.

This change still leaves incorrect restoration behavior due to the resize
anchor, but the symptoms are much severe in that case because it doesn't
touch page scale.

NOTRY=true
BUG=698315
Review-Url: https://codereview.chromium.org/2745313002
Cr-Commit-Position: refs/heads/master@{#456495}
(cherry picked from commit 80da37a9ae40452f920fdb8a5bbd55454f7e560c)

Review-Url: https://codereview.chromium.org/2746083003 .
Cr-Commit-Position: refs/branch-heads/3029@{#167}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed: https://chromium.googlesource.com/chromium/src/+/b302bdacad3416b46336402624990a9a4de1a0d2

[aelias_OOO_until_Jul13, 2017-03-13 21:41:27]

Description was changed from

==========
Avoid rotation anchor during transitional fullscreen states.

FullscreenController::isFullscreen is called exclusively by
WebViewImpl::resizeWithBrowserControls to exclude use of rotation
anchor.  The reason is that anchors incorrectly interpret the initial
offset restoration in FullscreenController::didUpdateLayout as a
layout-induced change.  Rotation anchors in particular tend to
snap page scale factor to extreme values as a result.

During the observed case, fullscreen state is still NeedsScrollAndStateRestore.
It's reasonable to consider every state in the machine other than "Initial"
(non-fullscreen) to count as fullscreen.

This change still leaves incorrect restoration behavior due to the resize
anchor, but the symptoms are much severe in that case because it doesn't
touch page scale.

NOTRY=true
BUG=698315

Review-Url: https://codereview.chromium.org/2745313002
Cr-Commit-Position: refs/heads/master@{#456495}
(cherry picked from commit 80da37a9ae40452f920fdb8a5bbd55454f7e560c)
==========

to

==========
Avoid rotation anchor during transitional fullscreen states.

FullscreenController::isFullscreen is called exclusively by
WebViewImpl::resizeWithBrowserControls to exclude use of rotation
anchor.  The reason is that anchors incorrectly interpret the initial
offset restoration in FullscreenController::didUpdateLayout as a
layout-induced change.  Rotation anchors in particular tend to
snap page scale factor to extreme values as a result.

During the observed case, fullscreen state is still NeedsScrollAndStateRestore.
It's reasonable to consider every state in the machine other than "Initial"
(non-fullscreen) to count as fullscreen.

This change still leaves incorrect restoration behavior due to the resize
anchor, but the symptoms are much severe in that case because it doesn't
touch page scale.

NOTRY=true
BUG=698315

Review-Url: https://codereview.chromium.org/2745313002
Cr-Commit-Position: refs/heads/master@{#456495}
(cherry picked from commit 80da37a9ae40452f920fdb8a5bbd55454f7e560c)

Review-Url: https://codereview.chromium.org/2746083003 .
Cr-Commit-Position: refs/branch-heads/3029@{#167}
Cr-Branched-From:
939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed:
https://chromium.googlesource.com/chromium/src/+/b302bdacad3416b4633640262499...
==========

[aelias_OOO_until_Jul13, 2017-03-13 21:41:28]

Committed patchset #1 (id:1) manually as
b302bdacad3416b46336402624990a9a4de1a0d2 (tree was closed).