Make textures register with GrResourceCache2 as scratch.

src/gpu/GrGpuResource.cpp

Index: src/gpu/GrGpuResource.cpp
diff --git a/src/gpu/GrGpuResource.cpp b/src/gpu/GrGpuResource.cpp
index a0a72785d9c74c0385e52d1b08da7beeac4eca99..bce7d2cae8b9c85661d1c9be14c9c63dd9ad5c53 100644
--- a/src/gpu/GrGpuResource.cpp
+++ b/src/gpu/GrGpuResource.cpp
@@ -22,7 +22,8 @@ GrGpuResource::GrGpuResource(GrGpu* gpu, bool isWrapped)
     : fGpu(gpu)
     , fRefCnt(1)
     , fCacheEntry(NULL)
-    , fUniqueID(CreateUniqueID()) {
+    , fUniqueID(CreateUniqueID())
+    , fScratchKey(GrResourceKey::NullScratchKey()) {
     if (isWrapped) {
         fFlags = kWrapped_FlagBit;
     } else {
@@ -72,6 +73,13 @@ GrContext* GrGpuResource::getContext() {
     }
 }
 
+void GrGpuResource::setScratchKey(const GrResourceKey& scratchKey) {
+    SkASSERT(fScratchKey.isNullScratch());
+    SkASSERT(scratchKey.isScratch());
+    SkASSERT(!scratchKey.isNullScratch());
+    fScratchKey = scratchKey;
+}
+
 uint32_t GrGpuResource::CreateUniqueID() {
     static int32_t gUniqueID = SK_InvalidUniqueID;
     uint32_t id;