Include GrRenderTarget.h in GrContext.h to unblock skia roll due to WK dependency on this include

Review URL: http://codereview.appspot.com/4927041/


git-svn-id: http://skia.googlecode.com/svn/trunk@2141 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/include/GrContext.h b/gpu/include/GrContext.h
index 44e0c04..2f64996 100644
--- a/gpu/include/GrContext.h
+++ b/gpu/include/GrContext.h
@@ -12,6 +12,9 @@
 
 #include "GrClip.h"
 #include "GrPaint.h"
+// not strictly needed but requires WK change in LayerTextureUpdaterCanvas to
+// remove.
+#include "GrRenderTarget.h" 
 
 class GrDefaultPathRenderer;
 class GrDrawTarget;
@@ -28,7 +31,6 @@
 class GrVertexBuffer;
 class GrVertexBufferAllocPool;
 
-
 class GR_API GrContext : public GrRefCnt {
 public:
     /**