Add default zoom functionality to chrome.tabs Zoom API.

chrome/common/extensions/docs/examples/api/tabs/zoom/popup.js

Index: chrome/common/extensions/docs/examples/api/tabs/zoom/popup.js
diff --git a/chrome/common/extensions/docs/examples/api/tabs/zoom/popup.js b/chrome/common/extensions/docs/examples/api/tabs/zoom/popup.js
index 1b0fcd8db3ed14f33cf68efec26d8a6c1f250709..d96bc74eff11af9bdf735262d510db85f725a784 100644
--- a/chrome/common/extensions/docs/examples/api/tabs/zoom/popup.js
+++ b/chrome/common/extensions/docs/examples/api/tabs/zoom/popup.js
@@ -49,6 +49,11 @@ document.addEventListener('DOMContentLoaded', function() {
         if (scopeRadios[i].value == zoomSettings.scope)
           scopeRadios[i].checked = true;
       }
+
+      var percentDefaultZoom =
+          parseFloat(zoomSettings.default_zoom_factor) * 100;
+      document.getElementById('defaultLabel').textContent =
+          'Default: ' + percentDefaultZoom.toFixed(1) + '%';
     });
 
     chrome.tabs.getZoom(tabId, displayZoomLevel);
@@ -92,7 +97,7 @@ function doZoomDefault() {
   if (tabId == -1)
     return;
 
-  chrome.tabs.setZoom(tabId, 1.0, function() {
+  chrome.tabs.setZoom(tabId, 0, function() {
     if (chrome.runtime.lastError)
       console.log('[ZoomDemoExtension] ' + chrome.runtime.lastError.message);
   });