Commit Graph

59 Commits

Author SHA1 Message Date
Brian Salomon
19f0ed5b83 Purge clip masks when they are no longer findable.
This improves memory usage when the content contains frequently changing clips implemented as masks.

BUG=chromium:676459

Change-Id: I06ea5f9fe1cff9564ea136bad9fe97f6ecd77ad9
Reviewed-on: https://skia-review.googlesource.com/6629
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
2017-01-06 19:42:08 +00:00
Mike Reed
c1f7774e8d Revert[2] "remove SK_SUPPORT_LEGACY_CLIP_REGIONOPS"
This reverts commit a129dfef2a.

BUG=skia:

Change-Id: I717de6e5fcd4516aa684b014b1414b0f82ac2b91
Reviewed-on: https://skia-review.googlesource.com/5722
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Derek Sollenberger <djsollen@google.com>
2016-12-09 14:33:41 +00:00
Mike Reed
a129dfef2a Revert "remove SK_SUPPORT_LEGACY_CLIP_REGIONOPS"
This reverts commit 8e7432b7f9.

Reason for revert: <INSERT REASONING HERE>

external/skia/bench/../tools/android/SkAndroidSDKCanvas.h:103:36: error: C++ requires a type specifier for all declarations
    void onClipRect(const SkRect&, ClipOp, ClipEdgeStyle) override;

Original change's description:
> remove SK_SUPPORT_LEGACY_CLIP_REGIONOPS
> 
> 
> switch over to SkClipOps now that SK_SUPPORT_LEGACY_CLIP_REGIONOPS is gone
> 
> BUG=skia:
> 
> Change-Id: Ifdc8b3746d508348a40cc009a4e529a1cb3c405d
> Reviewed-on: https://skia-review.googlesource.com/5714
> Commit-Queue: Mike Reed <reed@google.com>
> Reviewed-by: Mike Reed <reed@google.com>
> 

TBR=reed@google.com,reviews@skia.org
BUG=skia:
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: If26ea91d7464615e43c1d3d2f726e337ff56b55c
Reviewed-on: https://skia-review.googlesource.com/5721
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
2016-12-09 13:14:41 +00:00
Mike Reed
8e7432b7f9 remove SK_SUPPORT_LEGACY_CLIP_REGIONOPS
switch over to SkClipOps now that SK_SUPPORT_LEGACY_CLIP_REGIONOPS is gone

BUG=skia:

Change-Id: Ifdc8b3746d508348a40cc009a4e529a1cb3c405d
Reviewed-on: https://skia-review.googlesource.com/5714
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
2016-12-08 21:45:27 +00:00
Brian Salomon
a3b45d4f7d Move clip CTM application to SkRasterClip and SkClipStack
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2866

Change-Id: I914a57d6ba128acc457e12586c99ba6766eb940c
Reviewed-on: https://skia-review.googlesource.com/2866
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
2016-10-03 19:32:07 +00:00
reed
73603f3c52 abstract name of clipping ops, to transtion to a more restricted set
SkRegion::Op --> SkCanvas::ClipOp (alias) --> SkClipOp

pre-CL needed in chrome : https://codereview.chromium.org/2355583002/

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2355483002

Review-Url: https://codereview.chromium.org/2355483002
2016-09-20 08:42:39 -07:00
csmartdalton
8d3f92a92b Make GrReducedClip's gen ID only apply to the element list
Renames fGenID to fElementsGenID and designates this value as
undefined when when the element list is empty.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2244223004

Review-Url: https://codereview.chromium.org/2244223004
2016-08-17 09:39:38 -07:00
csmartdalton
d211e7875d Convert GrAppliedClip interface to builder style
GrAppliedClip was about at its limit for how many "make" functions it
could have. Window rectangles would push it over the edge. This change
makes it so GrDrawTarget supplies the original draw bounds to the
constructor, and then GrClip adds the various required clipping
techniques.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2246113002

Review-Url: https://codereview.chromium.org/2246113002
2016-08-15 11:17:19 -07:00
csmartdalton
77f2fae49e Encapsulate GrReducedClip result in class members
Updates GrReducedClip to store its result in class members instead of
various pointer arguments. This helps clean up calling code and will
make it easier to reduce the clip higher in the stack.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2222873002

Review-Url: https://codereview.chromium.org/2222873002
2016-08-08 09:55:06 -07:00
csmartdalton
cbecb082d1 Allow GrReducedClip to take non-integer query bounds
Fixes places where AA bloat was being conflated with geometric
boundaries and updates GrReducedClip to work with non-integer query
bounds. This allows for better clip reduction with AA shared edges.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2160093002

Review-Url: https://codereview.chromium.org/2160093002
2016-07-22 08:59:08 -07:00
csmartdalton
d50e240178 Fix SkClipStack bug with inverse-filled difference elements
Previously, SkClipStack would call "setEmpty" on itself when an
inverse-filled difference element made the stack empty. This was
a problem because setEmpty would forget the element had an inverse
fill, yet leave the op as "difference". This change modifies it to
manually update the clip bounds and set the gen-ID to kEmptyGenID,
rather than calling setEmpty.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2175493002

Review-Url: https://codereview.chromium.org/2175493002
2016-07-22 08:39:06 -07:00
bsalomon
00ee2a8482 Make all parameters reqiured to GrReducedClip::ReduceClipStack
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2130903002

Review-Url: https://codereview.chromium.org/2130903002
2016-07-08 03:28:34 -07:00
halcanary
4dbbd04314 SkLeanWindows.h: #include "Windows.h" fewer places
$ git grep -l '<windows.h>' include src
    include/private/SkLeanWindows.h

    $ git grep -l SkLeanWindows.h | grep '\.h$'
    include/ports/SkTypeface_win.h
    include/utils/win/SkHRESULT.h
    include/utils/win/SkTScopedComPtr.h
    include/views/SkEvent.h
    src/core/SkMathPriv.h
    src/ports/SkTypeface_win_dw.h
    src/utils/SkThreadUtils_win.h
    src/utils/win/SkWGL.h

The same for  `#include <intrin.h>` that was found in SkMath.h.
Those functions that needed it are moved to SkMathPriv.h.

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2041943002

CQ_INCLUDE_TRYBOTS=tryserver.chromium.win:win_chromium_compile_dbg_ng,win_chromium_compile_rel_ng

Review-Url: https://codereview.chromium.org/2041943002
2016-06-07 17:21:10 -07:00
halcanary
96fcdcc219 Style Change: NULL->nullptr
DOCS_PREVIEW= https://skia.org/?cl=1316233002

Review URL: https://codereview.chromium.org/1316233002
2015-08-27 07:41:16 -07:00
bsalomon
49f085dddf "NULL !=" = NULL
R=reed@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/544233002
2014-09-05 13:34:00 -07:00
commit-bot@chromium.org
e5b2af955b Store SkRRects in SkClipStack
BUG=skia:2181
R=robertphillips@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/163683002

git-svn-id: http://skia.googlecode.com/svn/trunk@13465 2bbb7eff-a529-9590-31e7-b0007b416f81
2014-02-16 13:25:24 +00:00
commit-bot@chromium.org
e2eac8b2fd Move macros from TestClassDef.h to Test.h
Motivation: those macros don't make any sense without the definitions
in Test.h.

BUG=
R=mtklein@google.com

Author: halcanary@google.com

Review URL: https://codereview.chromium.org/138563004

git-svn-id: http://skia.googlecode.com/svn/trunk@13074 2bbb7eff-a529-9590-31e7-b0007b416f81
2014-01-14 21:04:37 +00:00
tfarina@chromium.org
e4fafb146e Use DEFINE_TESTCLASS_SHORT macro in tests.
The three version of DEFINE_TESTCLASS macro is deprecated and thus just
use the simple, short one.

BUG=None
TEST=out/Debug/tests
R=mtklein@google.com, bsalomon@google.com, robertphillips@google.com

Review URL: https://codereview.chromium.org/100113004

git-svn-id: http://skia.googlecode.com/svn/trunk@12653 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-12-12 21:11:12 +00:00
commit-bot@chromium.org
d3e5842db0 Avoid re-rendering stencil clip for every draw with reducable clip stack
Fixes the cases where clip stack reduction would cause clip to be
re-rendered to stencil for each draw call. This causes unneeded
slowdown.

Stencil cache would not be used because the clip stack generation id communicated
by the clip stack element list would be invalid. This happended due to

 a) clip stack reduction creating new elements in the element list.

 b) purging logic removing the generation id, but reduction logic
    selecting already purged element, and thus the generation id, as
    the representative state of the clip.

Cases of a) where reduction would flatten the stack to a single new
element were fixed by assigning the generation id of the top-most
element of the clip stack as the generation id of the new
element. This is not strictly minimal, but enables more caching than
using invalid id.

Cases of a) where reduction would substitute a stack element with a
new element the generation id of the substituted element is used.

The b) part was fixed by removing the purging logic. It was not
exactly correct, as the previously purged states were actually
used. The purging was not used for anything.

Changes SkClipStack API to highlight that invalid generation id is
never returned by SkClipStack. Empty stacks are wide open. Changes the
clients to reflect this.

Fixes a crash when not passing anti-alias out parameter to
GrReducedClip::ReduceClipStack. The crash is not exercised in the
current code.

Committed: http://code.google.com/p/skia/source/detail?r=12084

R=bsalomon@google.com, robertphillips@google.com

Author: kkinnunen@nvidia.com

Review URL: https://codereview.chromium.org/48593003

git-svn-id: http://skia.googlecode.com/svn/trunk@12127 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-11-05 15:03:08 +00:00
reed@google.com
f0784bde75 Revert "Avoid re-rendering stencil clip for every draw with reducable clip stack"
This reverts commit 92a7d4bf6a371f1f864154be902e8d86938e560b.

Revert "fix mac 10.6 build"

This reverts commit 114cd1a9f2734aaed6914718814364811b78bd7f.

BUG=

Review URL: https://codereview.chromium.org/54543008

git-svn-id: http://skia.googlecode.com/svn/trunk@12087 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-11-01 16:25:59 +00:00
reed@google.com
eea3ab78e9 fix mac 10.6 build
- double -> float implicit conversion (for literals like 1.3)
- locally defined (and named) struct

R=scroggo@google.com

Review URL: https://codereview.chromium.org/56103002

git-svn-id: http://skia.googlecode.com/svn/trunk@12086 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-11-01 16:15:01 +00:00
commit-bot@chromium.org
679eb674fc Avoid re-rendering stencil clip for every draw with reducable clip stack
Fixes the cases where clip stack reduction would cause clip to be
re-rendered to stencil for each draw call. This causes unneeded
slowdown.

Stencil cache would not be used because the clip stack generation id communicated
by the clip stack element list would be invalid. This happended due to

 a) clip stack reduction creating new elements in the element list.

 b) purging logic removing the generation id, but reduction logic
    selecting already purged element, and thus the generation id, as
    the representative state of the clip.

Cases of a) where reduction would flatten the stack to a single new
element were fixed by assigning the generation id of the top-most
element of the clip stack as the generation id of the new
element. This is not strictly minimal, but enables more caching than
using invalid id.

Cases of a) where reduction would substitute a stack element with a
new element the generation id of the substituted element is used.

The b) part was fixed by removing the purging logic. It was not
exactly correct, as the previously purged states were actually
used. The purging was not used for anything.

Changes SkClipStack API to highlight that invalid generation id is
never returned by SkClipStack. Empty stacks are wide open. Changes the
clients to reflect this.

Fixes a crash when not passing anti-alias out parameter to
GrReducedClip::ReduceClipStack. The crash is not exercised in the
current code.

R=bsalomon@google.com, robertphillips@google.com

Author: kkinnunen@nvidia.com

Review URL: https://codereview.chromium.org/48593003

git-svn-id: http://skia.googlecode.com/svn/trunk@12084 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-11-01 15:24:20 +00:00
commit-bot@chromium.org
4b7d673089 More clang warning fixes.
Mostly unused functions and variables removed.

BUG=None
TEST=ninja -C out/Debug most
     ninja -C out/Release most

R=bsalomon@google.com, caryclark@google.com, robertphillips@google.com

Author: tfarina@chromium.org

Review URL: https://codereview.chromium.org/27933002

git-svn-id: http://skia.googlecode.com/svn/trunk@11884 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-10-21 16:41:00 +00:00
commit-bot@chromium.org
e0e7cfe44b Change old PRG to be SkLCGRandom; change new one to SkRandom
The goal here is to get people to start using the new random number
generator, while leaving the old one in place so we don't have to 
rebaseline GMs.

R=reed@google.com, bsalomon@google.com

Author: jvanverth@google.com

Review URL: https://chromiumcodereview.appspot.com/23576015

git-svn-id: http://skia.googlecode.com/svn/trunk@11169 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-09-09 20:09:12 +00:00
commit-bot@chromium.org
6fbe54c663 Compact the clipstack for kReplace_Op'd geometry
When adding a clip rect or clip path to the stack with the
kReplace_Op operation, remove all previous elements within the
same save frame (elements with fSaveCount equal to the current
fSaveCount of the stack). This prevents unbounded growth of the
clipstack for long-lived instances that gets reused.

Addresses https://code.google.com/p/skia/issues/detail?id=748

R=robertphillips@google.com

Author: fs@opera.com

Review URL: https://chromiumcodereview.appspot.com/16160020

git-svn-id: http://skia.googlecode.com/svn/trunk@9502 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-06-11 11:01:48 +00:00
jvanverth@google.com
c490f801b0 Change random number generator for 'tests' to SkMWCRandom. Also removes some
unused headers and fixes a couple of bugs exposed by changing the random 
number generator:

First, the function SkMatrix::getMaxStretch() had an error where it was testing
the square of a number against near-zero. This led to it occasionally taking a
cheaper but imprecise path for computing the eigenvalues of the matrix. It's 
been replaced with a check against the square of SK_ScalarNearlyZero. 

The second case was a failure in ClipStackTest, where it hit the rare case of 
a practically empty clip stack (it has a single Union) and we set a tight 
bounds. The bounds rect doesn't get set by GrReducedClip::ReduceClipStack() in 
this case, so when it clips the reduced stack it's clipping against garbage, 
and the resulting regions don't match. The solution is to initialize the 
tightBounds rect.


git-svn-id: http://skia.googlecode.com/svn/trunk@7952 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-03-04 13:56:38 +00:00
humper@google.com
05af1afd42 eliminate all warnings in non-thirdparty code on mac
Most of these issues were due to functions whose definitions appear in header files; I changed those functions to be 'static inline' instead of just 'static' or 'inline', which kills the warning for such functions.

Other functions that were static or anonymous-namespaced but were unused in cpp files were probably called at some point but are no longer; someone who knows more than I do should probably scrub all the functions I either deleted or #if 0'ed out and make sure that the right thing is happening here.

Lots of unused variables removed, and one nasty const issue handled.

There remains a single warning in thirdparty/externals/cityhash/src/city.cc on line 146 related to a signed/unsigned mismatch.  I don't know if we have control over this library so I didn't fix this one, but perhaps someone could do something about that one.

BUG=

Review URL: https://codereview.appspot.com/7067044

git-svn-id: http://skia.googlecode.com/svn/trunk@7051 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-01-07 16:47:43 +00:00
skia.committer@gmail.com
306ab9d5de Sanitizing source files in Skia_Periodic_House_Keeping
git-svn-id: http://skia.googlecode.com/svn/trunk@6774 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-12-13 02:01:33 +00:00
junov@chromium.org
8cdf0f52ff Adding quickContains API method to SkClipStack
BUG=http://code.google.com/p/chromium/issues/detail?id=164580
TEST=unit test ClipStack/quickContains
Review URL: https://codereview.appspot.com/6919044

git-svn-id: http://skia.googlecode.com/svn/trunk@6760 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-12-12 17:58:15 +00:00
junov@chromium.org
edf32d5b0e Fixing SkClipStack::clipDevPath so that it will not convert rectangular paths to rectangle clips if inverse fill.
BUG=http://code.google.com/p/chromium/issues/detail?id=164580
TEST=unit test ClipStackTest/test_rect_inverse_fill
Review URL: https://codereview.appspot.com/6880044

git-svn-id: http://skia.googlecode.com/svn/trunk@6731 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-12-10 14:57:54 +00:00
bsalomon@google.com
34cd70a581 Make the clip reducer operate on int rects. Remove redundant Gr from func
name.

R=robertphillips@google.com
Review URL: https://codereview.appspot.com/6890045

git-svn-id: http://skia.googlecode.com/svn/trunk@6688 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-12-06 14:23:20 +00:00
bsalomon@google.com
170bd792e1 Move GrReducedClip to its own files.
R=robertphillips@google.com
Review URL: https://codereview.appspot.com/6891045

git-svn-id: http://skia.googlecode.com/svn/trunk@6686 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-12-05 22:26:11 +00:00
skia.committer@gmail.com
73b140a9f6 Sanitizing source files in Skia_Periodic_House_Keeping
git-svn-id: http://skia.googlecode.com/svn/trunk@6669 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-12-05 02:01:21 +00:00
bsalomon@google.com
a444430281 Make GrReduceClipStack use a caller provided query rect rather than return a
bounds.

R=robertphillips@google.com
Review URL: https://codereview.appspot.com/6865059

git-svn-id: http://skia.googlecode.com/svn/trunk@6665 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-12-04 15:22:12 +00:00
bsalomon@google.com
8182fa0cac Make SkClipStack::Iter use SkClipStack::Element.
R=robertphillips@google.com
Review URL: https://codereview.appspot.com/6871051

git-svn-id: http://skia.googlecode.com/svn/trunk@6661 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-12-04 14:06:06 +00:00
bsalomon@google.com
5fac58c91d Remove SkClipStack::Iter::combinedNext.
Review URL: https://codereview.appspot.com/6844114

git-svn-id: http://skia.googlecode.com/svn/trunk@6619 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-11-29 21:14:59 +00:00
bsalomon@google.com
edb26fdb83 Set empty/wide-open genID on clip stack in more places and fix a bug in GrReduceClipStack.
R=robertphillips@google.com
Review URL: https://codereview.appspot.com/6847116

git-svn-id: http://skia.googlecode.com/svn/trunk@6579 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-11-28 14:42:41 +00:00
bsalomon@google.com
26daa8bbee Temporarily disable clip stack reduce test while working on fix.
git-svn-id: http://skia.googlecode.com/svn/trunk@6567 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-11-27 16:50:14 +00:00
bsalomon@google.com
705e840944 Make the clip stack reduction test generate inverse filled paths.
Also adds some comments to GrReduceClipStack.

R=robertphillips@google.com
Review URL: https://codereview.appspot.com/6847109

git-svn-id: http://skia.googlecode.com/svn/trunk@6561 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-11-27 15:43:57 +00:00
skia.committer@gmail.com
8ccf590b89 Sanitizing source files in Skia_Periodic_House_Keeping
git-svn-id: http://skia.googlecode.com/svn/trunk@6556 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-11-27 02:01:19 +00:00
bsalomon@google.com
e7b3d29a12 Actually fix GPU-less build.
git-svn-id: http://skia.googlecode.com/svn/trunk@6555 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-11-26 21:42:32 +00:00
bsalomon@google.com
a4e13c85b2 Fix GPU-less build.
Unreviewed.



git-svn-id: http://skia.googlecode.com/svn/trunk@6554 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-11-26 21:38:37 +00:00
bsalomon@google.com
51a6286c24 Add a function that computes a reduced representation of the clip stack.
Also adds a unit test. The function is not yet used other than in the test.
Review URL: https://codereview.appspot.com/6855098

git-svn-id: http://skia.googlecode.com/svn/trunk@6553 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-11-26 21:19:43 +00:00
skia.committer@gmail.com
72b2e6fff3 Sanitizing source files in Skia_Periodic_House_Keeping
git-svn-id: http://skia.googlecode.com/svn/trunk@6344 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-11-08 02:03:56 +00:00
bsalomon@google.com
e8ca6c6e3a Combine multiple intersecting rects in SkClipStack::Iter.
R=robertphillips@google.com
Review URL: https://codereview.appspot.com/6816104

git-svn-id: http://skia.googlecode.com/svn/trunk@6339 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-11-07 21:19:10 +00:00
bsalomon@google.com
100abf49e1 Shut up some Mac (xcode 3) warnings
Review URL: http://codereview.appspot.com/6503053/



git-svn-id: http://skia.googlecode.com/svn/trunk@5402 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-09-05 17:40:04 +00:00
rmistry@google.com
d6176b0dca Result of running tools/sanitize_source_files.py (which was added in https://codereview.appspot.com/6465078/)
This CL is part II of IV (I broke down the 1280 files into 4 CLs).
Review URL: https://codereview.appspot.com/6474054

git-svn-id: http://skia.googlecode.com/svn/trunk@5263 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-08-23 18:14:13 +00:00
robertphillips@google.com
08eacc1447 Added check for aa/bw rect merging
http://codereview.appspot.com/6449079/



git-svn-id: http://skia.googlecode.com/svn/trunk@4907 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-08-02 12:49:00 +00:00
robertphillips@google.com
7b11289b4e Added dev- & canv- prefixes to Ganesh bounding boxes to indicate coordinate space
http://codereview.appspot.com/6457061/



git-svn-id: http://skia.googlecode.com/svn/trunk@4856 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-07-31 15:18:21 +00:00
robertphillips@google.com
cc6493bbef Added ctor to SkClipStack and isEmpty method
http://codereview.appspot.com/6444048/



git-svn-id: http://skia.googlecode.com/svn/trunk@4787 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-07-26 18:39:13 +00:00