Support multiple null GL contexts on a thread.

Support multiple null GL contexts on a thread.

This has the side effect of requiring SkNullGLContext to use the null GL interface.

It exposes SkNullGLContext and also removes null context support from SampleApp.

Committed: https://skia.googlesource.com/skia/+/bb0502eec5c66ddd2f54330711010aabfa1c2176

[bsalomon, 2015-02-11 03:35:10]

bsalomon@google.com changed reviewers:
+ robertphillips@google.com, vmiura@chromium.org

[bsalomon, 2015-02-11 03:35:11]

Victor found that our null GL context doesn't support multiple instances or
contexts crossing threads. Chromium unit tests use our null contexts and he is
adding threaded rasterization.

https://codereview.chromium.org/916733002/diff/20001/src/gpu/gl/SkNullGLConte...
File src/gpu/gl/SkNullGLContext.cpp (right):

https://codereview.chromium.org/916733002/diff/20001/src/gpu/gl/SkNullGLConte...
src/gpu/gl/SkNullGLContext.cpp:20: class BufferObj {
git recognizes that this file is more similar to the prev version of
GrGLCreateNullInterface.cpp than to SkNullGLContext.cpp but rietveld does not.
:(

I pasted the contents of GrGLCreateNullInterface.cpp here and made a few
changes, as noted in following comments.

The static decl of current_context() above the /////s above this comment is new.

https://codereview.chromium.org/916733002/diff/20001/src/gpu/gl/SkNullGLConte...
src/gpu/gl/SkNullGLContext.cpp:118: struct SkNullGLContext::ContextState {
This was "struct ThreadContext" in the old file.

https://codereview.chromium.org/916733002/diff/20001/src/gpu/gl/SkNullGLConte...
src/gpu/gl/SkNullGLContext.cpp:135: static ContextState* Get() {
This function replaces these lines from the old file:

    static void* Create() { return SkNEW(ThreadContext ); }	
    static void Delete(void* context) { SkDELETE(reinterpret_cast<ThreadContext
*>(context)); }

https://codereview.chromium.org/916733002/diff/20001/src/gpu/gl/SkNullGLConte...
src/gpu/gl/SkNullGLContext.cpp:142: typedef SkNullGLContext::ContextState State;
new in this file

https://codereview.chromium.org/916733002/diff/20001/src/gpu/gl/SkNullGLConte...
src/gpu/gl/SkNullGLContext.cpp:169: State* state = State::Get();
I did a file-global search and replace for:

ThreadContext* ctx = ThreadContext::Get();
==>
State* state = State::Get();

and

ctx->
==>
state->

https://codereview.chromium.org/916733002/diff/20001/src/gpu/gl/SkNullGLConte...
src/gpu/gl/SkNullGLContext.cpp:343: static const GrGLInterface*
create_null_interface() {
This was renamed from GrGLCreateNullInterface and made static.

https://codereview.chromium.org/916733002/diff/20001/src/gpu/gl/SkNullGLConte...
src/gpu/gl/SkNullGLContext.cpp:489:
//////////////////////////////////////////////////////////////////////////////
everything below here is not part of the copy/paste of
GrGLCreateNullInterface.cpp

[bsalomon, 2015-02-11 03:35:24]

bsalomon@google.com changed reviewers:
- vmiura@chromium.org

[robertphillips, 2015-02-11 14:40:41]

lgtm

[bsalomon, 2015-02-11 19:00:40]

New patchsets have been uploaded after l-g-t-m from robertphillips@google.com

[bsalomon, 2015-02-11 19:05:15]

On 2015/02/11 14:40:41, robertphillips wrote:
> lgtm

I had to add back the old implementation until Chrome is updated to use
SkNullGLContext.h

[bsalomon, 2015-02-11 19:05:17]

On 2015/02/11 14:40:41, robertphillips wrote:
> lgtm

I had to add back the old implementation until Chrome is updated to use
SkNullGLContext.h

[bsalomon, 2015-02-11 19:05:24]

The CQ bit was checked by bsalomon@google.com

[commit-bot: I haz the power, 2015-02-11 19:05:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/916733002/40001

[commit-bot: I haz the power, 2015-02-11 19:11:16]

Committed patchset #3 (id:40001) as
https://skia.googlesource.com/skia/+/bb0502eec5c66ddd2f54330711010aabfa1c2176