cc: Don't use partial updates for scrollbars when they are not allowed.

cc/test/fake_scrollbar_layer.cc

Index: cc/test/fake_scrollbar_layer.cc
diff --git a/cc/test/fake_scrollbar_layer.cc b/cc/test/fake_scrollbar_layer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7d5d96865e4a82dd7b878689f9c0b1dadb9c3219
--- /dev/null
+++ b/cc/test/fake_scrollbar_layer.cc
@@ -0,0 +1,38 @@
+// Copyright 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "cc/test/fake_scrollbar_layer.h"
+
+#include "cc/test/fake_scrollbar_theme_painter.h"
+#include "cc/test/fake_web_scrollbar.h"
+#include "cc/test/fake_web_scrollbar_theme_geometry.h"
+
+namespace cc {
+
+FakeScrollbarLayer::FakeScrollbarLayer(
+    bool paint_during_update, int scrolling_layer_id)
+    : ScrollbarLayer(
+        FakeWebScrollbar::create().PassAs<WebKit::WebScrollbar>(),
+        FakeScrollbarThemePainter::Create(paint_during_update)
+        .PassAs<ScrollbarThemePainter>(),
+        FakeWebScrollbarThemeGeometry::create()
+        .PassAs<WebKit::WebScrollbarThemeGeometry>(),
+        scrolling_layer_id),
+      update_count_(0) {
+  setAnchorPoint(gfx::PointF(0, 0));
+  setBounds(gfx::Size(1, 1));
+  setIsDrawable(true);
+}
+
+FakeScrollbarLayer::~FakeScrollbarLayer() {}
+
+void FakeScrollbarLayer::update(
+    ResourceUpdateQueue& queue,
+    const OcclusionTracker* occlusion,
+    RenderingStats& stats) {
+  ScrollbarLayer::update(queue, occlusion, stats);
+  update_count_++;
+}
+
+}  // namespace cc