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

cc/gl_renderer_unittest.cc

Index: cc/gl_renderer_unittest.cc
diff --git a/cc/gl_renderer_unittest.cc b/cc/gl_renderer_unittest.cc
index 89603b1ece65c8fc80ad1e4ae92a6678a0ed091f..24cddf5fee2f16d2e654f4304b26f988811abcab 100644
--- a/cc/gl_renderer_unittest.cc
+++ b/cc/gl_renderer_unittest.cc
@@ -119,6 +119,14 @@ public:
     using GLRenderer::drawQuad;
     using GLRenderer::beginDrawingFrame;
     using GLRenderer::finishDrawingQuadList;
+
+    void clearFramebuffer(DrawingFrame& frame) {
+      // Check that scissor test is disabled unless we're using scissor
+      // as optimization when usingPartialSwap is on.
+      if (!capabilities().usingPartialSwap)
+          EXPECT_FALSE(isScissorEnabledForTesting());

[danakj, 2013/01/29 00:00:46]

Do we have any unit tests that would fail this without your changes in
direct_renderer.cc? Which one(s)?

+      GLRenderer::clearFramebuffer(frame);
+    }
 };
 
 class GLRendererTest : public testing::Test {