Support shared GL contexts in GrContextFactory

Mostly plumbing, plus some minimal testing to make sure that
the platform APIs don't explode. I plan to add testing of
SkCrossContextImageData using this, which should verify that
textures are actually shared.

Also found a factory and some related code in the
CommandBuffer test context that was totally unused.
BUG=skia:

Change-Id: I05bbc22c4d1ef946b702a5cc7f67788785219c62
Reviewed-on: https://skia-review.googlesource.com/8808
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/tools/gpu/gl/debug/DebugGLTestContext.cpp b/tools/gpu/gl/debug/DebugGLTestContext.cpp
index cf8a9e4240..e8eea8f78e 100644
--- a/tools/gpu/gl/debug/DebugGLTestContext.cpp
+++ b/tools/gpu/gl/debug/DebugGLTestContext.cpp
@@ -1208,7 +1208,10 @@ private:
 }  // anonymous namespace
 
 namespace sk_gpu_test {
-GLTestContext* CreateDebugGLTestContext() {
+GLTestContext* CreateDebugGLTestContext(GLTestContext* shareContext) {
+    if (shareContext) {
+        return nullptr;
+    }
     GLTestContext* ctx = new DebugGLContext();
     if (ctx->isValid()) {
         return ctx;