Add deferred count to GrResource.

This will be used to determine whether a resource can either be deleted or reinserted in the cache when its ref count reaches zero.
Review URL: https://codereview.appspot.com/7202046

git-svn-id: http://skia.googlecode.com/svn/trunk@7355 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrResource.cpp b/src/gpu/GrResource.cpp
index 002c262..8fb21e8 100644
--- a/src/gpu/GrResource.cpp
+++ b/src/gpu/GrResource.cpp
@@ -13,8 +13,9 @@
 SK_DEFINE_INST_COUNT(GrResource)
 
 GrResource::GrResource(GrGpu* gpu, bool isWrapped) {
-    fGpu        = gpu;
-    fCacheEntry = NULL;
+    fGpu              = gpu;
+    fCacheEntry       = NULL;
+    fDeferredRefCount = 0;
     if (isWrapped) {
         fFlags = kWrapped_Flag;
     } else {
@@ -25,6 +26,7 @@
 
 GrResource::~GrResource() {
     // subclass should have released this.
+    GrAssert(0 == fDeferredRefCount);
     GrAssert(!this->isValid());
 }