Implementing TabManager extensions API Discard Function.

chrome/browser/extensions/api/tabs/tabs_api.cc

 // Copyright (c) 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 "chrome/browser/extensions/api/tabs/tabs_api.h"
 
 #include <stddef.h>
 #include <algorithm>
 #include <limits>
 #include <memory>
@@ skipping 2150 matching lines @@
   api::tabs::ZoomSettings zoom_settings;
   ZoomModeToZoomSettings(zoom_mode, &zoom_settings);
   zoom_settings.default_zoom_factor.reset(new double(
       content::ZoomLevelToZoomFactor(zoom_controller->GetDefaultZoomLevel())));
 
   results_ = api::tabs::GetZoomSettings::Results::Create(zoom_settings);
   SendResponse(true);
   return true;
 }
 
+ExtensionFunction::ResponseAction TabsDiscardFunction::Run() {
+  std::unique_ptr<tabs::Discard::Params> params(
+      tabs::Discard::Params::Create(*args_));
+  EXTENSION_FUNCTION_VALIDATE(params);
+
+  WebContents* contents = nullptr;
+  Profile* profile = Profile::FromBrowserContext(browser_context());
+  // If |tab_id| is given, find the web_contents respective to it.
+  // Otherwise invoke discard function in TabManager with null web_contents
+  // that will discard the least important tab.
+  if (params->tab_id) {
+    int tab_id = *params->tab_id;
+    if (!GetTabById(tab_id, profile, include_incognito(), nullptr, nullptr,
+                    &contents, nullptr, &error_)) {
+      return RespondNow(Error(error_));
+    }
+  }
+  // Discard the tab.
+  contents =
+      g_browser_process->GetTabManager()->DiscardTabByExtension(contents);
+
+  // Create result to be returned. We have to return the Tab object
+  // in case of success (contents is not null) and undefined otherwise.
+  if (contents) {
+    return RespondNow(ArgumentList(tabs::Discard::Results::Create(
+        *ExtensionTabUtil::CreateTabObject(contents))));
+  } else {

[Devlin, 2016/07/25 15:48:55]

nit: no need for an else {} after a return.

[Anderson Silva, 2016/07/25 17:42:00]

Done.

+    return RespondNow(NoArguments());
+  }
+}
+
+TabsDiscardFunction::TabsDiscardFunction() {}
+TabsDiscardFunction::~TabsDiscardFunction() {}
+
 }  // namespace extensions