Task Manager: Make double-clicking on an extension do something useful.

chrome/browser/task_management/providers/web_contents/extension_task.cc

Index: chrome/browser/task_management/providers/web_contents/extension_task.cc
diff --git a/chrome/browser/task_management/providers/web_contents/extension_task.cc b/chrome/browser/task_management/providers/web_contents/extension_task.cc
index 9e6da132398dc92de57dfc0a6d46ab3a8f4b768e..4fffb451eef90ef8d57b54bbbb986f83e319ef85 100644
--- a/chrome/browser/task_management/providers/web_contents/extension_task.cc
+++ b/chrome/browser/task_management/providers/web_contents/extension_task.cc
@@ -5,6 +5,10 @@
 #include "chrome/browser/task_management/providers/web_contents/extension_task.h"
 
 #include "base/strings/utf_string_conversions.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_finder.h"
+#include "chrome/browser/ui/chrome_pages.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/web_contents.h"
 #include "extensions/browser/view_type_utils.h"
@@ -41,7 +45,8 @@ ExtensionTask::ExtensionTask(content::WebContents* web_contents,
     : RendererTask(GetExtensionTitle(web_contents, extension, view_type),
                    GetDefaultIcon(),
                    web_contents,
-                   web_contents->GetRenderProcessHost()) {
+                   web_contents->GetRenderProcessHost()),
+      extension_id_(extension->id()) {

[afakhry, 2016/05/25 18:50:59]

I applied this locally and flashed it on a chromeos device. This causes a crash
on startup. |extension| is nullptr.

That's why in GetExtensionTitle() and LoadExtensionIcon() we always check for
|extension| not being null. You need to account for this.

[ncarter (slow), 2016/05/25 19:59:09]

Yuck. Thanks for figuring that out.

   LoadExtensionIcon(extension);
 }
 
@@ -58,6 +63,19 @@ void ExtensionTask::UpdateFavicon() {
   // extension.
 }
 
+void ExtensionTask::Activate() {
+  // TODO(nick): For extensions::VIEW_TYPE_APP_WINDOW, and maybe others, there
+  // may actually be a window we could focus. Special case those here as needed.
+  Browser* browser = chrome::FindTabbedBrowser(
+      Profile::FromBrowserContext(web_contents()->GetBrowserContext()), true);
+
+  // If an existing browser isn't found, don't create a new one.
+  if (!browser)
+    return;
+
+  chrome::ShowExtensions(browser, extension_id_);
+}
+
 Task::Type ExtensionTask::GetType() const {
   return Task::EXTENSION;
 }