Implement pinch-zoom scaling for main-frame scrollbars and pinch-zoom overlay scrollbars.

cc/scrollbar_layer.cc

Index: cc/scrollbar_layer.cc
diff --git a/cc/scrollbar_layer.cc b/cc/scrollbar_layer.cc
index 6fad23cb11481dd7b64811a269b10d5fe873779f..d4479061f7525f5a9eece799ee6855e6995a8a39 100644
--- a/cc/scrollbar_layer.cc
+++ b/cc/scrollbar_layer.cc
@@ -17,6 +17,9 @@
 
 namespace cc {
 
+scoped_ptr<WebKit::WebScrollbarThemeGeometry> ScrollbarLayer::s_defaultGeometry;
+bool ScrollbarLayer::s_usesOverlayScrollbars = false;
+
 scoped_ptr<LayerImpl> ScrollbarLayer::createLayerImpl(LayerTreeImpl* treeImpl)
 {
     return ScrollbarLayerImpl::create(treeImpl, id(), ScrollbarGeometryFixedThumb::create(make_scoped_ptr(m_geometry->clone()))).PassAs<LayerImpl>();
@@ -26,21 +29,54 @@ scoped_refptr<ScrollbarLayer> ScrollbarLayer::create(
     scoped_ptr<WebKit::WebScrollbar> scrollbar,
     scoped_ptr<ScrollbarThemePainter> painter,
     scoped_ptr<WebKit::WebScrollbarThemeGeometry> geometry,
+    int scrollLayerId, bool isPinchZoomScrollbar)
+{
+    return make_scoped_refptr(new ScrollbarLayer(scrollbar.Pass(), painter.Pass(), geometry.Pass(), scrollLayerId, isPinchZoomScrollbar));
+}
+
+scoped_refptr<ScrollbarLayer> ScrollbarLayer::create(
+    scoped_ptr<WebKit::WebScrollbar> scrollbar,
+    scoped_ptr<ScrollbarThemePainter> painter,
     int scrollLayerId)
 {
-    return make_scoped_refptr(new ScrollbarLayer(scrollbar.Pass(), painter.Pass(), geometry.Pass(), scrollLayerId));
+    if (!s_defaultGeometry)
+        return make_scoped_refptr(static_cast<ScrollbarLayer*>(0));
+    return create(scrollbar.Pass(), painter.Pass(),
+        make_scoped_ptr(s_defaultGeometry->clone()).Pass(),
+        scrollLayerId, true);
+}
+
+void ScrollbarLayer::setDefaultGeometry(
+    WebKit::WebScrollbarThemeGeometry* themeGeometry)
+{
+    // We assume themeGeometry is ours to own.
+    if (themeGeometry)
+        s_defaultGeometry = make_scoped_ptr(themeGeometry);
+}
+
+WebKit::WebScrollbarThemeGeometry* ScrollbarLayer::cloneDefaultGeometry()
+{
+    if (s_defaultGeometry)
+        return s_defaultGeometry->clone();
+    return 0;
+}
+
+void ScrollbarLayer::setDefaultUsesOverlayScrollbars(bool usesOverlayScrollbars)
+{
+    s_usesOverlayScrollbars = usesOverlayScrollbars;
 }
 
 ScrollbarLayer::ScrollbarLayer(
     scoped_ptr<WebKit::WebScrollbar> scrollbar,
     scoped_ptr<ScrollbarThemePainter> painter,
     scoped_ptr<WebKit::WebScrollbarThemeGeometry> geometry,
-    int scrollLayerId)
+    int scrollLayerId, bool isPinchZoomScrollbar)
     : m_scrollbar(scrollbar.Pass())
     , m_painter(painter.Pass())
     , m_geometry(geometry.Pass())
     , m_scrollLayerId(scrollLayerId)
     , m_textureFormat(GL_INVALID_ENUM)
+    , m_isPinchZoomScrollbar(isPinchZoomScrollbar)
 {
     if (!m_scrollbar->isOverlay())
         setShouldScrollOnMainThread(true);
@@ -123,6 +159,8 @@ void ScrollbarLayer::pushPropertiesTo(LayerImpl* layer)
         scrollbarLayer->setThumbResourceId(m_thumb->texture()->resourceId());
     else
         scrollbarLayer->setThumbResourceId(0);
+
+    scrollbarLayer->setIsPinchZoomScrollbar(m_isPinchZoomScrollbar);
 }
 
 ScrollbarLayer* ScrollbarLayer::toScrollbarLayer()