Split drawing functionality out of GrContext and into new GrDrawContext

src/gpu/GrTest.cpp

Index: src/gpu/GrTest.cpp
diff --git a/src/gpu/GrTest.cpp b/src/gpu/GrTest.cpp
index 0801d03a6c59c31a10ab4266dca935be0b1bc1a1..fd962a1b078f549e0e21e96f8801f77837a46688 100644
--- a/src/gpu/GrTest.cpp
+++ b/src/gpu/GrTest.cpp
@@ -26,7 +26,7 @@ void GrContext::getTestTarget(GrTestTarget* tar) {
     // then disconnects. This would help prevent test writers from mixing using the returned
     // GrDrawTarget and regular drawing. We could also assert or fail in GrContext drawing methods
     // until ~GrTestTarget().
-    tar->init(this, fDrawBuffer);
+    tar->init(this, fDrawingMgr.fDrawTarget);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -264,7 +264,5 @@ void GrContext::initMockContext() {
     // We delete these because we want to test the cache starting with zero resources. Also, none of
     // these objects are required for any of tests that use this context. TODO: make stop allocating
     // resources in the buffer pools.
-    SkDELETE(fDrawBuffer);
-    fDrawBuffer = NULL;
-
+    fDrawingMgr.abandon();
 }