Revert of Discard scratch render targets before reusing them.

src/gpu/GrContext.cpp

Index: src/gpu/GrContext.cpp
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index 8084557c933ff236d3d804ac4212681d799042c5..89548ab5c956ee4fd066cef2774746ef8264de18 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -457,11 +457,6 @@
         // Ensure we have exclusive access to the texture so future 'find' calls don't return it
         resource = fTextureCache->find(key, GrResourceCache::kHide_OwnershipFlag);
         if (NULL != resource) {
-            // If the scratch texture is a render target, discard its contents.
-            GrRenderTarget* rt = static_cast<GrTexture*>(resource)->asRenderTarget();
-            if (NULL != rt) {
-                rt->discard();
-            }
             resource->ref();
             break;
         }