add per-draw checks for lockcounts

Review URL: https://codereview.appspot.com/6943056

git-svn-id: http://skia.googlecode.com/svn/trunk@6815 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 7 insertions, 0 deletions

diff --git a/src/core/SkDraw.cpp b/src/core/SkDraw.cpp
index 2f748d9930..b6eb6825d6 100644
--- a/src/core/SkDraw.cpp
+++ b/src/core/SkDraw.cpp
@@ -2424,6 +2424,13 @@ void SkDraw::drawVertices(SkCanvas::VertexMode vmode, int count,
     }
 
     SkAutoBlitterChoose blitter(*fBitmap, *fMatrix, p);
+    // important that we abort early, as below we may manipulate the shader
+    // and that is only valid if the shader returned true from setContext.
+    // If it returned false, then our blitter will be the NullBlitter.
+    if (blitter->isNullBlitter()) {
+        return;
+    }
+
     // setup our state and function pointer for iterating triangles
     VertState       state(count, indices, indexCount);
     VertState::Proc vertProc = state.chooseProc(vmode);