Original patch from issue 570048

chrome/browser/extensions/extension_tabs_module.cc

 // Copyright (c) 2011 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 "chrome/browser/extensions/extension_tabs_module.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/base64.h"
@@ skipping 935 matching lines @@
 
   // Close the tab in this convoluted way, since there's a chance that the tab
   // is being dragged, or we're in some other nested event loop. This code path
   // should ensure that the tab is safely closed under such circumstances,
   // whereas |Browser::CloseTabContents()| does not.
   RenderViewHost* render_view_host = contents->render_view_host();
   render_view_host->delegate()->Close(render_view_host);
   return true;
 }
 
+bool SetZoomPercentTabFunction::RunImpl() {
+  int tab_id;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &tab_id));
+
+  double zoom_percent = 0;
+  if (!args_->GetDouble(1, &zoom_percent)) {
+    int int_zoom_percent = 0;
+    EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(1, &int_zoom_percent));

[Aaron Boodman, 2011/02/07 09:26:55]

The renderer can never legitimately send anything else, so we can use
EXTENSION_FUNCTION_VALIDATE here.

+    zoom_percent = int_zoom_percent;
+  }
+  EXTENSION_FUNCTION_VALIDATE(zoom_percent >= 0);

[Aaron Boodman, 2011/02/07 09:26:55]

Same here (had to fix a bug in json_schema.js first).

+
+  Browser* browser = NULL;
+  TabContentsWrapper* contents = NULL;
+  if (!GetTabById(tab_id, profile(), include_incognito(),
+                  &browser, NULL, &contents, NULL, &error_)) {
+    return false;
+  }
+
+  // Store the tab id for later
+  tab_id_ = tab_id;
+
+  request_id_ = contents->tab_contents()->SetZoomPercent(zoom_percent);
+
+  // Need to wait until the render process responds to the request
+  // before we can respond to the extension request.
+  registrar_.Add(this,
+                 NotificationType::ZOOM_LEVEL_CHANGED,
+                 NotificationService::AllSources());
+  AddRef();  // Balanced in SetZoomPercentTabFunction::Observe().
+
+  return true;
+}
+
+void SetZoomPercentTabFunction::Observe(NotificationType type,
+                                        const NotificationSource& source,
+                                        const NotificationDetails& details) {
+  CHECK(type == NotificationType::ZOOM_LEVEL_CHANGED);

[Aaron Boodman, 2011/02/07 09:26:55]

I prefer CHECK to DCHECK since it will generate crash reports and tell us
something has gone wrong.

+
+  // Wait for our specific request
+  int observed_request_id = *Details<int>(details).ptr();
+  if (observed_request_id != request_id_)
+    return;
+
+  Browser* browser = NULL;
+  TabContentsWrapper* contents = NULL;
+  if (!GetTabById(tab_id_, profile(), include_incognito(),
+                  &browser, NULL, &contents, NULL, &error_)) {
+    Release(); // Balanced in SetZoomPercentTabFunction::RunImpl
+    return;
+  }
+
+  bool enable_inc_ignored = false;
+  bool enable_dec_ignored = false;
+  double zoom_percent = contents->tab_contents()->GetZoomPercent(
+    &enable_inc_ignored, &enable_dec_ignored);
+
+  result_.reset(Value::CreateDoubleValue(zoom_percent));
+  SendResponse(true);
+  Release(); // Balanced in SetZoomPercentTabFunction::RunImpl
+}
+
+bool GetZoomPercentTabFunction::RunImpl() {
+  int tab_id;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &tab_id));
+
+  Browser* browser = NULL;
+  TabContentsWrapper* contents = NULL;
+  if (!GetTabById(tab_id, profile(), include_incognito(),
+                  &browser, NULL, &contents, NULL, &error_)) {
+    return false;
+  }
+
+  bool enable_inc_ignored;
+  bool enable_dec_ignored;
+  double zoom_percent = contents->tab_contents()->GetZoomPercent(
+    &enable_inc_ignored, &enable_dec_ignored);
+
+  result_.reset(Value::CreateDoubleValue(zoom_percent));
+  return true;
+}
+
 bool CaptureVisibleTabFunction::RunImpl() {
   Browser* browser;
   // windowId defaults to "current" window.
   int window_id = -1;
 
   if (HasOptionalArgument(0)) {
     EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &window_id));
     browser = GetBrowserInProfileWithId(profile(), window_id,
                                         include_incognito(), &error_);
   } else {
@@ skipping 275 matching lines @@
 }
 
 static GURL ResolvePossiblyRelativeURL(std::string url_string,
                                        const Extension* extension) {
   GURL url = GURL(url_string);
   if (!url.is_valid())
     url = extension->GetResourceURL(url_string);
 
   return url;
 }