Add flag bits for partial GrContext reset

BUG=248728
R=bsalomon@google.com

Committed: https://code.google.com/p/skia/source/detail?r=9802

Review URL: https://codereview.chromium.org/17027003

git-svn-id: http://skia.googlecode.com/svn/trunk@9814 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/GrContext.h b/include/gpu/GrContext.h
index 5c796b2..c59c4d4 100644
--- a/include/gpu/GrContext.h
+++ b/include/gpu/GrContext.h
@@ -61,8 +61,10 @@
      * within the underlying 3D API's context/device/whatever. This call informs
      * the context that the state was modified and it should resend. Shouldn't
      * be called frequently for good performance.
+     * The flag bits, state, is dpendent on which backend is used by the
+     * context, either GL or D3D (possible in future).
      */
-    void resetContext();
+    void resetContext(uint32_t state = kAll_GrBackendState);
 
     /**
      * Callback function to allow classes to cleanup on GrContext destruction.