Fixes a bug when the framebuffer is cleared with invalid scissor rect

cc/direct_renderer.cc

Index: cc/direct_renderer.cc
diff --git a/cc/direct_renderer.cc b/cc/direct_renderer.cc
index 31f48e5f935be6f4e1fd88d49c5b8824067c417a..f9fb233671d17a9a8ecdd374a84be3bcdf8a9a12 100644
--- a/cc/direct_renderer.cc
+++ b/cc/direct_renderer.cc
@@ -240,8 +240,11 @@ void DirectRenderer::drawRenderPass(DrawingFrame& frame, const RenderPass* rende
         setScissorTestRect(moveScissorToWindowSpace(frame, renderPassScissor));
     }
 
-    if (frame.currentRenderPass != frame.rootRenderPass || m_client->shouldClearRootRenderPass())
+    if (frame.currentRenderPass != frame.rootRenderPass || m_client->shouldClearRootRenderPass()) {
+        if (!usingScissorAsOptimization)
+            ensureScissorTestDisabled();
         clearFramebuffer(frame);
+    }
 
     const QuadList& quadList = renderPass->quad_list;
     for (QuadList::constBackToFrontIterator it = quadList.backToFrontBegin(); it != quadList.backToFrontEnd(); ++it) {