Plumb in flag for reusing scratch textures

src/gpu/GrDrawTargetCaps.h

Index: src/gpu/GrDrawTargetCaps.h
===================================================================
--- src/gpu/GrDrawTargetCaps.h	(revision 10153)
+++ src/gpu/GrDrawTargetCaps.h	(working copy)
@@ -36,6 +36,7 @@
     bool bufferLockSupport() const { return fBufferLockSupport; }
     bool pathStencilingSupport() const { return fPathStencilingSupport; }
     bool dstReadInShaderSupport() const { return fDstReadInShaderSupport; }
+    bool reuseScratchTextures() const { return fReuseScratchTextures; }
 
     int maxRenderTargetSize() const { return fMaxRenderTargetSize; }
     int maxTextureSize() const { return fMaxTextureSize; }
@@ -54,6 +55,7 @@
     bool fBufferLockSupport         : 1;
     bool fPathStencilingSupport     : 1;
     bool fDstReadInShaderSupport    : 1;
+    bool fReuseScratchTextures      : 1;
 
     int fMaxRenderTargetSize;
     int fMaxTextureSize;