Make SkGLContext lifetime more well-defined

tests/GrContextFactoryTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkTypes.h"
 
 #if SK_SUPPORT_GPU
@@ skipping 28 matching lines @@
         GrContextFactory::GLContextType glCtxType = (GrContextFactory::GLContextType)i;
         GrContext* context = testFactory.get(glCtxType);
         if (context) {
             REPORTER_ASSERT(
                 reporter,
                 !context->caps()->shaderCaps()->pathRenderingSupport());
         }
     }
 }
 
+DEF_GPUTEST(GrContextFactory_abandon, reporter, /*factory*/) {
+    GrContextFactory testFactory;
+    for (int i = 0; i < GrContextFactory::kGLContextTypeCnt; ++i) {
+        GrContextFactory::GLContextType glCtxType = (GrContextFactory::GLContextType) i;
+        GrContextFactory::ContextInfo info1 =
+                testFactory.getContextInfo(glCtxType);
+        if (!info1.fGrContext) {
+            continue;
+        }
+        REPORTER_ASSERT(reporter, info1.fGLContext);
+         // Ref for comparison. The API does not explicitly say that this stays alive.
+        info1.fGrContext->ref();
+        testFactory.abandonContexts();
+
+        // Test that we get different context after abandon.
+        GrContextFactory::ContextInfo info2 =
+                testFactory.getContextInfo(glCtxType);
+        REPORTER_ASSERT(reporter, info2.fGrContext);
+        REPORTER_ASSERT(reporter, info2.fGLContext);
+        REPORTER_ASSERT(reporter, info1.fGrContext != info2.fGrContext);
+        // fGLContext should also change, but it also could get the same address.
+
+        info1.fGrContext->unref();
+    }
+}
+
 #endif