Add zoom extension API

chrome/browser/tab_contents/tab_contents.cc

Index: chrome/browser/tab_contents/tab_contents.cc
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index 2f946be16bb945a3a29a5caff2461bab3e7b1847..08d9d1ea687a81c2bf91640448ad2f95433de5b8 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -1448,6 +1448,14 @@ void TabContents::UpdateHistoryPageTitle(const NavigationEntry& entry) {
     hs->SetPageTitle(entry.virtual_url(), entry.title());
 }
 
+int TabContents::SetZoomLevel(double zoom_level) {
+  static int request_id = -1;
+
+  request_id++;
+  render_view_host()->SetZoomLevel(request_id, zoom_level);
+  return request_id;
+}
+
 double TabContents::GetZoomLevel() const {
   HostZoomMap* zoom_map = profile()->GetHostZoomMap();
   if (!zoom_map)
@@ -1463,11 +1471,17 @@ double TabContents::GetZoomLevel() const {
   return zoom_level;
 }
 
-int TabContents::GetZoomPercent(bool* enable_increment,
+int TabContents::SetZoomPercent(double zoom_percent) {
+  double zoom_level;
+  zoom_level = WebKit::WebView::zoomFactorToZoomLevel(zoom_percent / 100);
+  return SetZoomLevel(zoom_level);
+}
+
+double TabContents::GetZoomPercent(bool* enable_increment,
                                 bool* enable_decrement) {
   *enable_decrement = *enable_increment = false;
-  int percent = static_cast<int>(
-      WebKit::WebView::zoomLevelToZoomFactor(GetZoomLevel()) * 100);
+  double percent;
+  percent = WebKit::WebView::zoomLevelToZoomFactor(GetZoomLevel()) * 100;
   *enable_decrement = percent > minimum_zoom_percent_;
   *enable_increment = percent < maximum_zoom_percent_;
   return percent;
@@ -1898,7 +1912,7 @@ void TabContents::UpdateWebPreferences() {
 }
 
 void TabContents::UpdateZoomLevel() {
-  render_view_host()->SetZoomLevel(GetZoomLevel());
+  SetZoomLevel(GetZoomLevel());
 }
 
 void TabContents::UpdateMaxPageIDIfNecessary(SiteInstance* site_instance,