Store pointers to GrGlyph directly in BitmapTextBlob

Store pointers to GrGlyph directly in BitmapTextBlob.  This patch improves performance by avoiding hashmap lookups under normal use

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/ae32c102e70577bff1432ef4b4b63ca6835012f6

[joshualitt, 2015-04-20 13:04:49]

joshualitt@google.com changed reviewers:
+ bsalomon@google.com, joshualitt@google.com, jvanverth@google.com

[joshualitt, 2015-04-20 13:04:50]

ptal

[jvanverth1, 2015-04-20 15:51:18]

I assume that this is to improve perf by removing hashmap lookups. If so, you
might want to put that in the description. O/w, lGtM.

[bsalomon, 2015-04-21 12:32:17]

lgtm

https://codereview.chromium.org/1087203004/diff/60001/src/gpu/GrAtlasTextCont...
File src/gpu/GrAtlasTextContext.cpp (right):

https://codereview.chromium.org/1087203004/diff/60001/src/gpu/GrAtlasTextCont...
src/gpu/GrAtlasTextContext.cpp:1543: 
Probably should have a parallel (but shorter) comment in the cache header where
it returns the grbatchtextstrike. Something like, "The user of the cache may
hold a long-lived ref to the returned strike. However, actions by another client
of the cache may cause the strike to be purged while it is still reffed.
Therefore, the caller must check GrBatchTextStrike::isAbandoned() if there are
other interactions the cache since the strike was received."

[joshualitt, 2015-04-21 15:51:50]

The CQ bit was checked by joshualitt@google.com

[joshualitt, 2015-04-21 15:51:50]

The patchset sent to the CQ was uploaded after l-g-t-m from
jvanverth@google.com, bsalomon@google.com
Link to the patchset: https://codereview.chromium.org/1087203004/#ps80001
(title: "adding comment")

[commit-bot: I haz the power, 2015-04-21 15:52:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1087203004/80001

[commit-bot: I haz the power, 2015-04-21 16:38:01]

Committed patchset #5 (id:80001) as
https://skia.googlesource.com/skia/+/ae32c102e70577bff1432ef4b4b63ca6835012f6