Move some theme images to being serviced on the IO thread. For

Linux Release builds on my machine, all the chrome://theme/ image
requests block for 300-400ms during browser startup (it's faster
after startup).  Something is blocking the UI thread so move
image requests that aren't themed off the UI thread.  This is
safe to do because ResourceBundle is thread safe.

I still see chrome://theme/theme_ntp_attribution and
chrome://theme/theme_ntp_background blocking so I will look
into those next (I think with the default theme, they shouldn't
be loaded at all).

Review URL: http://codereview.chromium.org/440009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@32985 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 16 insertions, 5 deletions

diff --git a/chrome/browser/dom_ui/dom_ui_theme_source.cc b/chrome/browser/dom_ui/dom_ui_theme_source.cc
index 3640c40..9fa4f25 100644
--- a/chrome/browser/dom_ui/dom_ui_theme_source.cc
+++ b/chrome/browser/dom_ui/dom_ui_theme_source.cc
@@ -79,6 +79,11 @@ MessageLoop* DOMUIThemeSource::MessageLoopForRequestPath(
     return NULL;
   }
 
+  // If it's not a themeable image, we don't need to go to the UI thread.
+  int resource_id = ThemeResourcesUtil::GetId(uncached_path);
+  if (!BrowserThemeProvider::IsThemeableImage(resource_id))
+    return NULL;
+
   return DataSource::MessageLoopForRequestPath(path);
 }
 
@@ -86,10 +91,16 @@ MessageLoop* DOMUIThemeSource::MessageLoopForRequestPath(
 // DOMUIThemeSource, private:
 
 void DOMUIThemeSource::SendThemeBitmap(int request_id, int resource_id) {
-  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
-  ThemeProvider* tp = profile_->GetThemeProvider();
-  DCHECK(tp);
+  if (BrowserThemeProvider::IsThemeableImage(resource_id)) {
+    DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+    ThemeProvider* tp = profile_->GetThemeProvider();
+    DCHECK(tp);
 
-  scoped_refptr<RefCountedMemory> image_data(tp->GetRawData(resource_id));
-  SendResponse(request_id, image_data);
+    scoped_refptr<RefCountedMemory> image_data(tp->GetRawData(resource_id));
+    SendResponse(request_id, image_data);
+  } else {
+    DCHECK(ChromeThread::CurrentlyOn(ChromeThread::IO));
+    const ResourceBundle& rb = ResourceBundle::GetSharedInstance();
+    SendResponse(request_id, rb.LoadDataResourceBytes(resource_id));
+  }
 }