Unpack theme data from extensions off of UI thread.

chrome/browser/ui/extensions/extension_install_ui_default.cc

Index: chrome/browser/ui/extensions/extension_install_ui_default.cc
diff --git a/chrome/browser/ui/extensions/extension_install_ui_default.cc b/chrome/browser/ui/extensions/extension_install_ui_default.cc
index 93dbebc5e5c576c547e7c08c7899868816610154..a0819ea53ee470c02695d23137a12316ac8f269f 100644
--- a/chrome/browser/ui/extensions/extension_install_ui_default.cc
+++ b/chrome/browser/ui/extensions/extension_install_ui_default.cc
@@ -9,7 +9,6 @@
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "chrome/browser/chrome_notification_types.h"
-#include "chrome/browser/extensions/theme_installed_infobar_delegate.h"
 #include "chrome/browser/infobars/infobar_service.h"
 #include "chrome/browser/prefs/incognito_mode_prefs.h"
 #include "chrome/browser/profiles/profile.h"
@@ -142,25 +141,13 @@ ExtensionInstallUIDefault::ExtensionInstallUIDefault(
     content::BrowserContext* context)
     : profile_(Profile::FromBrowserContext(context)),
       skip_post_install_ui_(false),
-      previous_using_system_theme_(false),
-      use_app_installed_bubble_(false) {
-  // |profile| can be NULL during tests.
-  if (profile_) {
-    // Remember the current theme in case the user presses undo.
-    const Extension* previous_theme =
-        ThemeServiceFactory::GetThemeForProfile(profile_);
-    if (previous_theme)
-      previous_theme_id_ = previous_theme->id();
-    previous_using_system_theme_ =
-        ThemeServiceFactory::GetForProfile(profile_)->UsingSystemTheme();
-  }
-}
+      use_app_installed_bubble_(false) {}
 
 ExtensionInstallUIDefault::~ExtensionInstallUIDefault() {}
 
 void ExtensionInstallUIDefault::OnInstallSuccess(const Extension* extension,
                                                  const SkBitmap* icon) {
-  if (skip_post_install_ui_)
+  if (skip_post_install_ui_ || extension->is_theme())
     return;
 
   if (!profile_) {
@@ -170,12 +157,6 @@ void ExtensionInstallUIDefault::OnInstallSuccess(const Extension* extension,
     return;
   }
 
-  if (extension->is_theme()) {
-    ThemeInstalledInfoBarDelegate::Create(

[Devlin, 2017/06/01 00:28:09]

Does moving this out of here and into ThemeService::OnThemeBuiltFromExtension()
result in the infobar being shown significantly later?  I think this method was
called prior to the theme initialization work, which meant there was some
instant UI feedback (though as the CL description notes, that feedback was a
little strange).  Is that correct?  If so, would it be worth keeping the bar
showing early?

[Evan Stade, 2017/06/01 17:43:02]

Before, the browser would immediately hang for a second or two, then when it
resumes functioning, the theme is present and the infobar is showing.

Now, the browser continues to work normally for a second or two, then the theme
and infobar show up after the unpacking delay.

The latter seems strictly preferable. Hanging as a means of "instant feedback"
doesn't seem like a win. :) I did not want to move the infobar's appearance to
before the theme actually installed because then you can press undo and nothing
happens.

[Devlin, 2017/06/01 18:19:58]

Okay, cool.  My concern was if before the flow was:
Click install
Infobar shows
Browser hangs

and now it would be
click install
<second gap>
infobar shows

If the flow was
click install
browser hangs
infobar shows

Then yes, this is definitely better. :)  I do still like your suggestion from
the CL description about showing the infobar sooner with some kind of status;
can we file a bug for that (or add it to the existing one)?

-        extension, profile_, previous_theme_id_, previous_using_system_theme_);
-    return;
-  }
-
   // Extensions aren't enabled by default in incognito so we confirm
   // the install in a normal window.
   Profile* current_profile = profile_->GetOriginalProfile();