Wait for URLBlacklist update tasks on automation tests.

chrome/browser/automation/testing_automation_provider.cc

Index: chrome/browser/automation/testing_automation_provider.cc
diff --git a/chrome/browser/automation/testing_automation_provider.cc b/chrome/browser/automation/testing_automation_provider.cc
index 58a04741f2109e7b289ffce7f17fd92bf98a8d0e..4f40946edfc0f95a236ab28dcdd872ae7c9a6583 100644
--- a/chrome/browser/automation/testing_automation_provider.cc
+++ b/chrome/browser/automation/testing_automation_provider.cc
@@ -20,6 +20,7 @@
 #include "base/process.h"
 #include "base/process_util.h"
 #include "base/stringprintf.h"
+#include "base/synchronization/waitable_event.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
@@ -176,6 +177,24 @@ class AutomationInterstitialPage : public InterstitialPage {
   DISALLOW_COPY_AND_ASSIGN(AutomationInterstitialPage);
 };
 
+// Waits for all currently pending tasks on |identifier| to be processed before
+// returning. Returns false if |identifier| is the current thread, or a task
+// could not be posted. Returns true otherwise.
+bool WaitForPendingTasksOn(BrowserThread::ID identifier) {
+  // Avoid deadlocking self.
+  if (BrowserThread::CurrentlyOn(identifier))
+    return false;
+  base::WaitableEvent event(true,    // manual reset
+                            false);  // not initially signaled
+  if (!BrowserThread::PostTask(
+      identifier,
+      FROM_HERE,
+      base::Bind(&base::WaitableEvent::Signal, base::Unretained(&event))))
+    return false;
+  event.Wait();

[Paweł Hajdan Jr., 2011/10/19 09:20:02]

I think this also returns bool, so please return event.Wait in that case.
Otherwise, please ignore.

+  return true;
+}
+
 }  // namespace
 
 TestingAutomationProvider::TestingAutomationProvider(Profile* profile)
@@ -2734,12 +2753,10 @@ namespace {
 // Used by AutomationProvider::GetBrowserInfo().
 class GetChildProcessHostInfoTask : public Task {
  public:
-  GetChildProcessHostInfoTask(base::WaitableEvent* event,
-                              ListValue* child_processes)
-    : event_(event),
-      child_processes_(child_processes) {}
+  explicit GetChildProcessHostInfoTask(ListValue* child_processes)
+      : child_processes_(child_processes) {}
 
-  virtual void Run() {
+  virtual void Run() OVERRIDE {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
     for (BrowserChildProcessHost::Iterator iter; !iter.Done(); ++iter) {
       // Only add processes which are already started,
@@ -2755,11 +2772,9 @@ class GetChildProcessHostInfoTask : public Task {
       item->SetInteger("pid", base::GetProcId(info->handle()));
       child_processes_->Append(item);
     }
-    event_->Signal();
   }
 
  private:
-  base::WaitableEvent* const event_;  // weak
   ListValue* child_processes_;
 
   DISALLOW_COPY_AND_ASSIGN(GetChildProcessHostInfoTask);
@@ -2881,12 +2896,10 @@ void TestingAutomationProvider::GetBrowserInfo(
   // Add all child processes in a list of dictionaries, one dictionary item
   // per child process.
   ListValue* child_processes = new ListValue;
-  base::WaitableEvent event(true   /* manual reset */,
-                            false  /* not initially signaled */);
   CHECK(BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
-      new GetChildProcessHostInfoTask(&event, child_processes)));
-  event.Wait();
+      new GetChildProcessHostInfoTask(child_processes)));
+  CHECK(WaitForPendingTasksOn(BrowserThread::IO));

[jam, 2011/10/19 23:56:27]

instead of blocking one thread on another, why not post a task to the other
thread and then have that post a task back to this thread, and then that second
task is what sends the reply message? this is the pattern that we use all over
chrome

   return_value->Set("child_processes", child_processes);
 
   // Add all extension processes in a list of dictionaries, one dictionary
@@ -5901,6 +5914,14 @@ void TestingAutomationProvider::SetPolicies(
     }
   }
 
+  // OverridePolicies() triggers preference updates, which triggers preference
+  // listeners. Some policies (e.g. URLBlacklist) post tasks to other message
+  // loops before they start being enforced; make sure those tasks have
+  // finished.
+  CHECK(WaitForPendingTasksOn(BrowserThread::IO));

[jam, 2011/10/19 23:56:27]

ditto

+  CHECK(WaitForPendingTasksOn(BrowserThread::FILE));
+  CHECK(WaitForPendingTasksOn(BrowserThread::IO));
+
   reply.SendSuccess(NULL);
 #endif  // defined(OFFICIAL_BUILD)
 }