app_shell: Fix PrefsTabHelper dependency of ExtensionHost

The default preference values are fine for app_shell's pages (as they are
for content_shell, which doesn't use PrefsTabHelper).  Delegate out the
creation of PrefsTabHelper so we only create them in Chrome.

With this patch app_shell can launch a renderer before crashing.

BUG=332435
TEST=browser_tests, manual testing that extensions still work

Review URL: https://codereview.chromium.org/132993002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244236 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 21 insertions, 2 deletions

diff --git a/apps/shell/shell_extensions_browser_client.cc b/apps/shell/shell_extensions_browser_client.cc
index 67af2ac..f745200 100644
--- a/apps/shell/shell_extensions_browser_client.cc
+++ b/apps/shell/shell_extensions_browser_client.cc
@@ -98,6 +98,10 @@ bool ShellExtensionsBrowserClient::IsBackgroundPageAllowed(
   return true;
 }
 
+void ShellExtensionsBrowserClient::OnExtensionHostCreated(
+    content::WebContents* web_contents) {
+}
+
 bool ShellExtensionsBrowserClient::DidVersionUpdate(BrowserContext* context) {
   // TODO(jamescook): We might want to tell extensions when app_shell updates.
   return false;
diff --git a/apps/shell/shell_extensions_browser_client.h b/apps/shell/shell_extensions_browser_client.h
index 61d7d7d..86781b5 100644
--- a/apps/shell/shell_extensions_browser_client.h
+++ b/apps/shell/shell_extensions_browser_client.h
@@ -39,6 +39,8 @@ class ShellExtensionsBrowserClient : public ExtensionsBrowserClient {
       const OVERRIDE;
   virtual bool IsBackgroundPageAllowed(content::BrowserContext* context)
       const OVERRIDE;
+  virtual void OnExtensionHostCreated(content::WebContents* web_contents)
+      OVERRIDE;
   virtual bool DidVersionUpdate(content::BrowserContext* context) OVERRIDE;
   virtual scoped_ptr<AppSorting> CreateAppSorting() OVERRIDE;
   virtual bool IsRunningInForcedAppMode() OVERRIDE;
diff --git a/chrome/browser/extensions/chrome_extensions_browser_client.cc b/chrome/browser/extensions/chrome_extensions_browser_client.cc
index da56988..e85e244 100644
--- a/chrome/browser/extensions/chrome_extensions_browser_client.cc
+++ b/chrome/browser/extensions/chrome_extensions_browser_client.cc
@@ -16,6 +16,7 @@
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/app_modal_dialogs/javascript_dialog_manager.h"
 #include "chrome/browser/ui/browser_finder.h"
+#include "chrome/browser/ui/prefs/prefs_tab_helper.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/chrome_version_info.h"
 #include "chrome/common/pref_names.h"
@@ -110,6 +111,11 @@ bool ChromeExtensionsBrowserClient::IsBackgroundPageAllowed(
   return true;
 }
 
+void ChromeExtensionsBrowserClient::OnExtensionHostCreated(
+    content::WebContents* web_contents) {
+  PrefsTabHelper::CreateForWebContents(web_contents);
+}
+
 bool ChromeExtensionsBrowserClient::DidVersionUpdate(
     content::BrowserContext* context) {
   Profile* profile = static_cast<Profile*>(context);
diff --git a/chrome/browser/extensions/chrome_extensions_browser_client.h b/chrome/browser/extensions/chrome_extensions_browser_client.h
index c90bc72..4552699 100644
--- a/chrome/browser/extensions/chrome_extensions_browser_client.h
+++ b/chrome/browser/extensions/chrome_extensions_browser_client.h
@@ -50,6 +50,8 @@ class ChromeExtensionsBrowserClient : public ExtensionsBrowserClient {
       content::BrowserContext* context) const OVERRIDE;
   virtual bool IsBackgroundPageAllowed(
       content::BrowserContext* context) const OVERRIDE;
+  virtual void OnExtensionHostCreated(content::WebContents* web_contents)
+      OVERRIDE;
   virtual bool DidVersionUpdate(content::BrowserContext* context) OVERRIDE;
   virtual scoped_ptr<AppSorting> CreateAppSorting() OVERRIDE;
   virtual bool IsRunningInForcedAppMode() OVERRIDE;
diff --git a/chrome/browser/extensions/extension_host.cc b/chrome/browser/extensions/extension_host.cc
index 6ca2501..bafcf21 100644
--- a/chrome/browser/extensions/extension_host.cc
+++ b/chrome/browser/extensions/extension_host.cc
@@ -21,7 +21,6 @@
 #include "chrome/browser/extensions/extension_tab_util.h"
 #include "chrome/browser/extensions/extension_web_contents_observer.h"
 #include "chrome/browser/media/media_capture_devices_dispatcher.h"
-#include "chrome/browser/ui/prefs/prefs_tab_helper.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/extensions/extension_messages.h"
@@ -142,7 +141,6 @@ ExtensionHost::ExtensionHost(const Extension* extension,
   SetViewType(host_contents_.get(), host_type);
 
   ExtensionWebContentsObserver::CreateForWebContents(host_contents());
-  PrefsTabHelper::CreateForWebContents(host_contents());
 
   render_view_host_ = host_contents_->GetRenderViewHost();
 
@@ -150,6 +148,8 @@ ExtensionHost::ExtensionHost(const Extension* extension,
   // be the same extension that this points to.
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_UNLOADED,
                  content::Source<BrowserContext>(browser_context_));
+
+  ExtensionsBrowserClient::Get()->OnExtensionHostCreated(host_contents());
 }
 
 ExtensionHost::~ExtensionHost() {
diff --git a/extensions/browser/extensions_browser_client.h b/extensions/browser/extensions_browser_client.h
index 306515f..46405a0 100644
--- a/extensions/browser/extensions_browser_client.h
+++ b/extensions/browser/extensions_browser_client.h
@@ -16,6 +16,7 @@ class PrefService;
 namespace content {
 class BrowserContext;
 class JavaScriptDialogManager;
+class WebContents;
 }
 
 namespace extensions {
@@ -75,6 +76,10 @@ class ExtensionsBrowserClient {
   virtual bool IsBackgroundPageAllowed(
       content::BrowserContext* context) const = 0;
 
+  // Called after the hosting |web_contents| for an extension is created. The
+  // implementation may wish to add preference observers to |web_contents|.
+  virtual void OnExtensionHostCreated(content::WebContents* web_contents) = 0;
+
   // Returns true if the client version has updated since the last run. Called
   // once each time the extensions system is loaded per browser_context. The
   // implementation may wish to use the BrowserContext to record the current