This CL contains the following changes:
- Add a variation selector argument into getFamilyForChar to be able to
  select fonts which support variation selector.
- In case no fonts support the codepoint and variation selector pair,
  add a fallback rule which selects font family with ignoring variation
  selector.
- Change FontCollection::itemize to not change the font family
  immediately preceding a variation selector.
- Introduce unit tests for variation selectors.

With this CL, TextView can render the variation selectors correctly.

Bug: 11256006
Change-Id: I22ce0e9eadc941f84e3a9b23462f194e51dd7180

* commit 'e8264e06':
  Complete half-done cherry-picking of Android.mk. DO NOT MERGE

MinikinFont:GetGlyph is no longer used.
No behavior chnages are expected with this CL.

Change-Id: I13398503841ac06f930b04815017d4b33338efa1

The previous commit, 6e2cccdc, was
incompletely cherry-picked. This adds the missing parts.

Bug: 24570591
Change-Id: I1097c60587fb8a88cfe6b8ffed5b1689d9bdd429

* commit 'e5e7aa0e':
  Explicitly set utf-8 encoding for hyb file verification

* commit '6e2cccdc':
  Binary format for hyphenation patterns

Not all platforms default to UTF-8 encoding, so we set it explicitly.
This patch should fix build breakages resulting from failed verification
of binary hyb files for hyphenation patterns.

Bug: 24570591
Change-Id: I65ac4536d3436586c2633e2b57554fc6ff16d3a8
(cherry picked from commit 138b93f0)

In the current state, hyphenation in all languages than Sanskrit seems
to work (case-folding edge cases). Thus, we just disable Sanskrit.
Packed tries are implemented, but not the finite state machine
(space/speed tradeoff).

This commit contains a throw-away test app, which runs on the host.
I think I want to replace it with unit tests, but I'm including it in
the CL because it's useful during development.

Bug: 21562869
Bug: 21826930
Bug: 23317038
Bug: 23317904
Bug: 24570591
Change-Id: I7479a565a4a062fa319651c2c14c0fa18c5ceaea
(cherry picked from commit f0be43de)

This CL introduces new method hasVariationSelector into FontFamily but it
is not used in production code. So no behavior changes are expected.

This CL contains the following changes:
- Introduce hasVariationSelector which returns true if the corresponding
  font has a glyph for a code point and variation selector pair.
- Introduce purgeHbFontCache since hb_face_t won't be released by
  keeping hb_font_t.
- Introduce unit tests with self-built font.

Change-Id: I659a6d03d9ec446b409e1fba2758452abb9f44fa

Not all platforms default to UTF-8 encoding, so we set it explicitly.
This patch should fix build breakages resulting from failed verification
of binary hyb files for hyphenation patterns.

Change-Id: I65ac4536d3436586c2633e2b57554fc6ff16d3a8

In the current state, hyphenation in all languages than Sanskrit seems
to work (case-folding edge cases). Thus, we just disable Sanskrit.
Packed tries are implemented, but not the finite state machine
(space/speed tradeoff).

This commit contains a throw-away test app, which runs on the host.
I think I want to replace it with unit tests, but I'm including it in
the CL because it's useful during development.

Bug: 21562869
Bug: 21826930
Bug: 23317038
Bug: 23317904

Change-Id: I7479a565a4a062fa319651c2c14c0fa18c5ceaea

This CL does following things:
- Extract hb_face_t object cache mechanism from Layout.cpp to be able to
  use it from other cpp file, especially from FontFamily.cpp.
  To address Bug 11256006 and Bug 17759267, need to touch
  hb_face_t from FontFamily.
- Make hb_face_t cache mechanism thread-safe.
- Add unit tests for HbFaceCache test cases.

Bug: 11256006
Bug: 17759267
Change-Id: Ic183634ef34326793bd9a32167236611d0af34d6

This doesn't change current behavior. It's a preparation
for the following CLs.

Bug: 22408712
Change-Id: Ic018422254aa3904655f499194caad74f0c0fc5d

Introduced tests depend on installed font list in running device.
I verified these test passed  on Nexus 5(hammerhead), Nexus 6(shamu)
and Nexus 9(volantis).

Bug: 11256006
Bug: 17759267
Change-Id: I6f806370e17f6c6d3dad8df0cb70bb475a827873

Currently codepoint to glyph ID resolution is done through MinikinFont
interface. To support variation selector, use HarfBuzz API instead of
calling this interface since one of its implementation Skia doesn't
support variation selector.

On the other hand, we don't want to get glyph horizontal advance values
by HarfBuzz since HarfBuzz doesn't return correct values when the hinting
is active.

Thus, use ot_font as a parent font and override
glyph_h_advance/glyph_h_origin functions as is.

With this change, MinikinFont::GetGlyph is no longer necessary but not
removing in this CL for easy reverting since removing interface requires
multi-repository commit.

This is a base work of b/11256006 and this patch doesn't provide any
user visible changes.

Bug: 11256006
Change-Id: I061172c0b674bb649ce8bc013ffecf38708bdc41

This CL does:
1. Move the getNextWordBreak/getPrevWordBreak function to a separate source file.
2. Adding "ForCache" suffix for function name for making clear these function is
   for layout cache.
3. Introduce unit tests for them.

Bug: 11256006
Change-Id: I4138751a4570915f1a0d6c8921f89700f8ec7f35

Initial unit tests for Minikin functionality. Also fixes an incorrect
Hangul case (uncovered in testing), and improves handling of broken
UTF-16.

Change-Id: I69b441d8e3b19ed06abcc56f13271abadf3d1010

Reported externally at https://code.google.com/p/android/issues/detail?id=167715.
Bug: 21498085

Change-Id: I73f22de03b0151ce31a6b3070d051a2a701b33d2

Also handle the case of weird language code that we don't understand
properly better, by treating them not equal to each other.

Change-Id: Iaccb251fa38d700932f6eadac254d3d1fa09b3ea

This tailors Unicode's Grapheme_Cluster_Break property to better
classify characters currently with the Control property value.

Also adds support for rule GB9b of UAX #29, needed since there are
now characters we are tailoring to be Prepend. The rule was
previously ommited in our implementation because there was no
characters in the Prepend class.

Bug: 15653110
Change-Id: If10da88df0980f7d676c8c0b950eda5fb8dbe741

In computing scores for which fallback font to choose, a match of a
variant given explicitly in the xml config file scores higher than a
family with no explicit variant. One consequence is that U+2010
HYPHEN is chosen from the Naskh Arabic font in the fallback case.

This patch scores families with no variants as a match (effectively
the same as if the xml file specified both variants). Thus, it will
choose the first matching font (Roboto), which is a better choice.

This patch also revises the list of "sticky" characters to include
various hyphens, so Arabic (and potentially other scripts) text that
includes hyphens can access the script-specific variants matched to
the underlying text.

Bug: 22824219
Change-Id: I6ec1043037f89cad50ca99ac24c473395546bcdf

This reverts commit 3e0fc64d.

Bug: 22589743
Bug: 22121742
Change-Id: I7b482ffb8a0ee174ddc804aa890de45bdbd758e3

It's essential not to apply a break opportunity within a replacement
span, otherwise things can happen such as displaying the span twice.
The old code tested this case based on zero-width characters.
However, this test was both imprecise, and also in some cases read
uninitialized values from the mCharWidths array, which in turn led
to inconsistent line breaking of the same text.

This patch applies all line break opportunities (as identified by
ICU) within text (as opposed to replacement spans), and also applies
break opportunities at the beginning and end of replacement spans,
but avoids breaks within a replacement span.

Bug: 20138621
Change-Id: I36baeb44d6808356649e1bb69ca57f093fc8c723

Previously, the standard C tolower() function was used, which
didn't support any characters beyond the basic ASCII letters.

Bug: 22506121
Change-Id: Ibb81121caa29be44fbb59aa98891e9faafc57592

This adds various hyphen-like characters missed in the previous
patch, that should disallow automatic hyphenation of words containing
them.

Bug: 22484266
Change-Id: Ie972cb50384dbe0aa1ab5ec50286b75f9877953a

Previously, automatic hyphenation blindly took almost every line
breaking opportunity as a word break, so words like "low-budget" were
treated as two separate words, "low-", and "budget", each
automatically hyphenated.

This patch makes sure the subwords in already-hyphenated phrases are
not passed to the automatic hyphenator, while keeping the possibility
of a potential line break where a hyphen already exists.

Bug: 22484266
Bug: 22287425
Change-Id: Ie46dbdd70e993d64a9b9cf44b4ae93b21459dbc2

We bypass the word layout cache for "complex" cases, which includes
things like OpenType features. We were counting a hyphen edit as such
a case, but the problem is that we measure a _lot_ of these when
doing layout with hyphenation.

This patch adds plumbing for hyphen edits to the layout cache, so
that word fragments with hyphens can be cached as well.

Bug: 22378829

Change-Id: Idba4df4faa14f48a5faccc8a7a7955a36c19ef27

The logic in getRunAdvance() assumed that any zero-width character was
part of the preceding cluster, which is valid most of the time. However,
characters such as ZWNBSP (U+FEFF) renders as a zero width glyph
and is also a grapheme cluster boundary. This patch adds a clause to
handle that case.

Bug: 22121742
Change-Id: Iad79a7d988bded1ef05f0fd7905d20669ea22051

An incorrect cluster offset calculation was causing a lot of log
messages to appear. Separately, a confusion between #if and #ifdef was
causing unintended logging of line breaks. This patch fixes both.

Bug: 22178333
Change-Id: I2b3673ed66c784f5082fd127a8dc10bd3df6ed79

The appearance of letterspacing with scripts with cursive connections
is poor, so we simply disable letterspacing for those scripts. There
may be some cases where some form of letterspacing is desirable, but
this gives the highest likelihood that the final result will be good
without requiring additional work from clients.

Bug: 21935803
Change-Id: Ie25266249ac3a2605aa89ef5132e8edbe3a06d35

A recent change added a penalty for a hyphen at the last line break,
which is visually undesirable. However, the penalty was assessed to
"widthScore", which broke the assumption (used for another
optimization) that widthScore increases monotonically. This patch
separates the penalty into a different parameter, restoring the
validity of the monotonicity assumption.

Bug: 22066119
Change-Id: I6a47a350ef3ceee2f00ee430d6954d0c307227f0

Previously, we just assumed the font in use had a U+2010 HYPHEN
character, resulting in a tofu (or an empty space) being shown when
U+2010 was not supported in the font used to render the hyphenated
word.

Now we try to fallback to U+002D HYPHEN-MINUS, which has a very good
chance of being available in at least any Latin font.

We still show a tofu when neither character is supported, to
intentionally alert that something is missing.

Bug: 20497913
Bug: 21088552
Bug: 21570828
Change-Id: Iff69bbc38836c03495e9124502b5207c39270da2