Change BrowserThreadDelegate to run Init() async.

android_webview/browser/aw_browser_context.cc

Index: android_webview/browser/aw_browser_context.cc
diff --git a/android_webview/browser/aw_browser_context.cc b/android_webview/browser/aw_browser_context.cc
index 06793fa217dada615a6aae52326524e9e1a86b4f..2664ccf91215c242967603a879af887f4c4d3b35 100644
--- a/android_webview/browser/aw_browser_context.cc
+++ b/android_webview/browser/aw_browser_context.cc
@@ -87,6 +87,7 @@ AwBrowserContext* AwBrowserContext::FromWebContents(
 void AwBrowserContext::InitializeBeforeThreadCreation() {
   DCHECK(!url_request_context_getter_.get());
   url_request_context_getter_ = new AwURLRequestContextGetter(this);
+  url_request_context_getter_->InitializeOnUiThread();

[awong, 2013/07/11 20:43:48]

I think we have to move this into PreMainMessageLoopRun for it to work. 
InitializeOnUiThread() calls CreateCookieStore() which calls
BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO), and
BrowserThread::GetBlockingPool()->GetSequencedTaskRunner().

I don't think these exist until after thread creation.

AFAICT there are no other delegates in AwBrowserContext which I think means that
all the message loops must be empty in PreMainMessageLoopRun.

If that logic sounds right, then I think it'd be cleaner to 
  (a) Make AwURLRequestContextGetter NOT a BrowserThreadDelegate
  (b) Move your AwURLRequestContextGetter::InitializeOnIiThread() to 
      CookieStore* AwBrowserContext::CreateCookieStore()
  (c) First thing in PreMainMesasgeLoopRun, do
      scoped_refptr<CookieStore> cookie_store = CreateCookieStore();
      url_request_context_getter_ = new AwURLRequestContextGetter(this);
      BrowserThread::PostTask(IO, FROM_HERE,
          Bind(&AwURLRequestContextGetter::InitOnIOThread, 
               url_request_context_getter_,
               cookie_store));

The upside of not being a BrowserThreadDelegate is that the threading
constraints are better understood.

Please push back on me if you think I'm missing something. This code is tricky
enough that I'm only 80% confident in my analysis.

[Maria, 2013/07/11 21:11:37]

I think you are correct that I cannot be creating the cookie store until we have
a message loop for IO thread. However, I don't like the suggestion fix below
because it relies on the current knowledge of there not being a
BrowserThreadDelegate -- if someone was to add it in the future, they would
break our assumptions of an empty message loop.

Instead, what do you think about changing BrowserThreadDelegate interface to
have three methods:

Init()
InitAsync()
CleanUp

Then we will have a delegate->Init() call followed by delegate->InitAsync() call
scheduled as the first call on the loop.

So we would rename IOThread::Init into InitAsync and InitializeOnUiThread would
become Init() method.


On 2013/07/11 20:43:48, awong wrote:

 }
 
 void AwBrowserContext::PreMainMessageLoopRun() {