Reland: Use FontFallbackPriority Fonts in FontFallbackIterator

Reland: Use FontFallbackPriority Fonts in FontFallbackIterator

Now that the pieces are in place, use the emoji and symbol fonts in
FontFallbackIterator. Previously FontCache's character fallback
functions were extended so that they take FontFallbackPriority into
account. These functions can now be used in FontFallbackIterator as a
fallback priority stage where those fonts are used as the first fallback
font in order to correctly distinguish between emoji and text
presentation emoji.

Relanded after revert in https://codereview.chromium.org/1758383002/
Rebaselining the test results since now the emoji font is used more
often.

Original issue LGTM'ed in https://codereview.chromium.org/1672553004/

BUG=549571, 591778
TBR=eae, behdad

Committed: https://crrev.com/508edd3841b53f2f6063c6a6ef58f34a4e41e71c
Cr-Commit-Position: refs/heads/master@{#379249}

[drott, 2016-03-04 07:18:27]

The CQ bit was checked by drott@chromium.org

[commit-bot: I haz the power, 2016-03-04 07:18:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1764933002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1764933002/1

[commit-bot: I haz the power, 2016-03-04 08:47:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-03-04 08:48:13]

Description was changed from

==========
Reland: Use FontFallbackPriority Fonts in FontFallbackIterator

Now that the pieces are in place, use the emoji and symbol fonts in
FontFallbackIterator. Previously FontCache's character fallback
functions were extended so that they take FontFallbackPriority into
account. These functions can now be used in FontFallbackIterator as a
fallback priority stage where those fonts are used as the first fallback
font in order to correctly distinguish between emoji and text
presentation emoji.

Relanded after revert in https://codereview.chromium.org/1758383002/
Rebaselining the test results since now the emoji font is used more
often.

Original issue LGTM'ed in https://codereview.chromium.org/1672553004/

BUG=549571,591778
TBR=eae, behdad
==========

to

==========
Reland: Use FontFallbackPriority Fonts in FontFallbackIterator

Now that the pieces are in place, use the emoji and symbol fonts in
FontFallbackIterator. Previously FontCache's character fallback
functions were extended so that they take FontFallbackPriority into
account. These functions can now be used in FontFallbackIterator as a
fallback priority stage where those fonts are used as the first fallback
font in order to correctly distinguish between emoji and text
presentation emoji.

Relanded after revert in https://codereview.chromium.org/1758383002/
Rebaselining the test results since now the emoji font is used more
often.

Original issue LGTM'ed in https://codereview.chromium.org/1672553004/

BUG=549571,591778
TBR=eae, behdad

Committed: https://crrev.com/508edd3841b53f2f6063c6a6ef58f34a4e41e71c
Cr-Commit-Position: refs/heads/master@{#379249}
==========

[commit-bot: I haz the power, 2016-03-04 08:48:16]

Patchset 1 (id:??) landed as
https://crrev.com/508edd3841b53f2f6063c6a6ef58f34a4e41e71c
Cr-Commit-Position: refs/heads/master@{#379249}