Extend FontCache fallback API to support FontFallbackPriority

Extend FontCache fallback API to support FontFallbackPriority

This is take two and now compatible with Android. Instead of retrieving
a list of font family candidates I am now extending the existing
character fallback API with the FontFallbackPriority argument. Depending
on the platform, this gives us better search options for finding the
fallback font. On Android specifically, we can search for the character
plus a specific locale for retrieving the color emoji font without an
explicit family name. In Windows, we can better integrate with the
existing fallback logic.

Unfortunately, this is change is hard to test on the bots as an Emoji
font is not available on all Linux bots and blink_platform_unittests do
currently not execute on Android. But the change was manually verified
on Mac, Windows, Linux and Android.

BUG=580536
Committed: https://crrev.com/18cda1ab960d4638738da618186b48a7598b4de0
Cr-Commit-Position: refs/heads/master@{#378826}

[drott, 2016-03-02 15:16:58]

drott@chromium.org changed reviewers:
+ eae@chromium.org, fmalita@chromium.org, leviw@chromium.org

[drott, 2016-03-02 15:17:06]

The CQ bit was checked by drott@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-03-02 15:17:20]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1757703003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1757703003/1

[commit-bot: I haz the power, 2016-03-02 16:31:58]

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

[commit-bot: I haz the power, 2016-03-02 16:31:59]

Dry run: This issue passed the CQ dry run.

[eae, 2016-03-02 18:26:54]

LGTM w/suggestions

https://codereview.chromium.org/1757703003/diff/1/third_party/WebKit/Source/p...
File third_party/WebKit/Source/platform/fonts/android/FontCacheAndroid.cpp
(right):

https://codereview.chromium.org/1757703003/diff/1/third_party/WebKit/Source/p...
third_party/WebKit/Source/platform/fonts/android/FontCacheAndroid.cpp:44: static
const char* kAndroidColorEmojiLocale = "und-Zsye";
Zsye? This could use  a comment explaining it.

https://codereview.chromium.org/1757703003/diff/1/third_party/WebKit/Source/p...
File third_party/WebKit/Source/platform/fonts/mac/FontCacheMac.mm (right):

https://codereview.chromium.org/1757703003/diff/1/third_party/WebKit/Source/p...
third_party/WebKit/Source/platform/fonts/mac/FontCacheMac.mm:56: const char*
kColorEmojiFontMac = { "Apple Color Emoji" };
Remove curly brackets.

https://codereview.chromium.org/1757703003/diff/1/third_party/WebKit/Source/p...
File third_party/WebKit/Source/platform/fonts/win/FontFallbackWin.cpp (right):

https://codereview.chromium.org/1757703003/diff/1/third_party/WebKit/Source/p...
third_party/WebKit/Source/platform/fonts/win/FontFallbackWin.cpp:500: UBlockCode
blockCode = fallbackPriority == FontFallbackPriority::EmojiEmoji ?
How about naming the variable block instead? Seems more consistent with how we
use script for UscriptCode etc.

[drott, 2016-03-02 19:31:02]

review comments addressed

[drott, 2016-03-02 19:31:30]

Thanks for the quick review, I incorporated those suggestions.

[drott, 2016-03-02 19:31:44]

The CQ bit was checked by drott@chromium.org

[drott, 2016-03-02 19:31:45]

The patchset sent to the CQ was uploaded after l-g-t-m from eae@chromium.org
Link to the patchset: https://codereview.chromium.org/1757703003/#ps20001
(title: "review comments addressed")

[commit-bot: I haz the power, 2016-03-02 19:32:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1757703003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1757703003/20001

[f(malita), 2016-03-02 20:10:00]

lgtm

[commit-bot: I haz the power, 2016-03-02 20:56:10]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-03-02 20:57:19]

Description was changed from

==========
Extend FontCache fallback API to support FontFallbackPriority

This is take two and now compatible with Android. Instead of retrieving
a list of font family candidates I am now extending the existing
character fallback API with the FontFallbackPriority argument. Depending
on the platform, this gives us better search options for finding the
fallback font. On Android specifically, we can search for the character
plus a specific locale for retrieving the color emoji font without an
explicit family name. In Windows, we can better integrate with the
existing fallback logic.

Unfortunately, this is change is hard to test on the bots as an Emoji
font is not available on all Linux bots and blink_platform_unittests do
currently not execute on Android. But the change was manually verified
on Mac, Windows, Linux and Android.

BUG=580536
==========

to

==========
Extend FontCache fallback API to support FontFallbackPriority

This is take two and now compatible with Android. Instead of retrieving
a list of font family candidates I am now extending the existing
character fallback API with the FontFallbackPriority argument. Depending
on the platform, this gives us better search options for finding the
fallback font. On Android specifically, we can search for the character
plus a specific locale for retrieving the color emoji font without an
explicit family name. In Windows, we can better integrate with the
existing fallback logic.

Unfortunately, this is change is hard to test on the bots as an Emoji
font is not available on all Linux bots and blink_platform_unittests do
currently not execute on Android. But the change was manually verified
on Mac, Windows, Linux and Android.

BUG=580536

Committed: https://crrev.com/18cda1ab960d4638738da618186b48a7598b4de0
Cr-Commit-Position: refs/heads/master@{#378826}
==========

[commit-bot: I haz the power, 2016-03-02 20:57:21]

Patchset 2 (id:??) landed as
https://crrev.com/18cda1ab960d4638738da618186b48a7598b4de0
Cr-Commit-Position: refs/heads/master@{#378826}