Make uncached textures uncached from the get go.

This avoids the problem of a newly created uncached texture causing a purge of cached resources.

BUG=chromium:445885

Review URL: https://codereview.chromium.org/846303002
diff --git a/src/gpu/GrTexture.cpp b/src/gpu/GrTexture.cpp
index eb518f5..378e990 100644
--- a/src/gpu/GrTexture.cpp
+++ b/src/gpu/GrTexture.cpp
@@ -118,11 +118,11 @@
 }
 
 //////////////////////////////////////////////////////////////////////////////
-GrTexture::GrTexture(GrGpu* gpu, bool isWrapped, const GrSurfaceDesc& desc)
-    : INHERITED(gpu, isWrapped, desc)
+GrTexture::GrTexture(GrGpu* gpu, LifeCycle lifeCycle, const GrSurfaceDesc& desc)
+    : INHERITED(gpu, lifeCycle, desc)
     , fMipMapsStatus(kNotAllocated_MipMapsStatus) {
 
-    if (!isWrapped) {
+    if (kCached_LifeCycle == lifeCycle) {
         GrScratchKey key;
         GrTexturePriv::ComputeScratchKey(desc, &key);
         this->setScratchKey(key);