Consider PlatformThread::Join() to be blocking IO.

Marks PlatformThread::Join() as blocking IO using ThreadRestrictions.
Whitelists existing spots where we join on the UI/IO threads.

Also noteworthy is I allow blocking IO on shutdown.

BUG=65530,66077,66082
TEST=none

Review URL: http://codereview.chromium.org/5693003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@68893 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 25 insertions, 0 deletions

diff --git a/base/platform_thread_posix.cc b/base/platform_thread_posix.cc
index e442e9c..9807ac6 100644
--- a/base/platform_thread_posix.cc
+++ b/base/platform_thread_posix.cc
@@ -219,5 +219,9 @@ bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) {
 
 // static
 void PlatformThread::Join(PlatformThreadHandle thread_handle) {
+  // Joining another thread may block the current thread for a long time, since
+  // the thread referred to by |thread_handle| may still be running long-lived /
+  // blocking tasks.
+  base::ThreadRestrictions::AssertIOAllowed();
   pthread_join(thread_handle, NULL);
 }
diff --git a/base/platform_thread_win.cc b/base/platform_thread_win.cc
index e5afc52..68e837e 100644
--- a/base/platform_thread_win.cc
+++ b/base/platform_thread_win.cc
@@ -125,6 +125,10 @@ bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) {
 // static
 void PlatformThread::Join(PlatformThreadHandle thread_handle) {
   DCHECK(thread_handle);
+  // Joining another thread may block the current thread for a long time, since
+  // the thread referred to by |thread_handle| may still be running long-lived /
+  // blocking tasks.
+  base::ThreadRestrictions::AssertIOAllowed();
 
   // Wait for the thread to exit.  It should already have terminated but make
   // sure this assumption is valid.
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index ea52797..8facb15 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -13,6 +13,7 @@
 #include "base/path_service.h"
 #include "base/task.h"
 #include "base/thread.h"
+#include "base/thread_restrictions.h"
 #include "base/waitable_event.h"
 #include "chrome/browser/appcache/chrome_appcache_service.h"
 #include "chrome/browser/automation/automation_provider_list.h"
@@ -252,6 +253,12 @@ unsigned int BrowserProcessImpl::ReleaseModule() {
   DCHECK_NE(0u, module_ref_count_);
   module_ref_count_--;
   if (0 == module_ref_count_) {
+    // Allow UI and IO threads to do blocking IO on shutdown, since we do a lot
+    // of it on shutdown for valid reasons.
+    base::ThreadRestrictions::SetIOAllowed(true);
+    io_thread()->message_loop()->PostTask(
+        FROM_HERE,
+        NewRunnableFunction(&base::ThreadRestrictions::SetIOAllowed, true));
     MessageLoop::current()->PostTask(
         FROM_HERE, NewRunnableFunction(DidEndMainMessageLoop));
     MessageLoop::current()->Quit();
diff --git a/chrome/browser/geolocation/geolocation_provider.cc b/chrome/browser/geolocation/geolocation_provider.cc
index 97e9049..3756af7 100644
--- a/chrome/browser/geolocation/geolocation_provider.cc
+++ b/chrome/browser/geolocation/geolocation_provider.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/geolocation/geolocation_provider.h"
 
 #include "base/singleton.h"
+#include "base/thread_restrictions.h"
 #include "chrome/browser/geolocation/location_arbitrator.h"
 
 // This class is guaranteed to outlive its internal thread, so ref counting
@@ -47,6 +48,10 @@ bool GeolocationProvider::RemoveObserver(GeolocationObserver* observer) {
 void GeolocationProvider::OnObserversChanged() {
   DCHECK(OnClientThread());
   if (observers_.empty()) {
+    // http://crbug.com/66077: This is a bug.  The geolocation thread may
+    // transitively (via other threads it joins) block on long-running tasks /
+    // IO.
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
     Stop();
   } else {
     if (!IsRunning()) {
diff --git a/chrome/browser/printing/printer_query.cc b/chrome/browser/printing/printer_query.cc
index c28f400..7b73d86 100644
--- a/chrome/browser/printing/printer_query.cc
+++ b/chrome/browser/printing/printer_query.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/printing/printer_query.h"
 
 #include "base/message_loop.h"
+#include "base/thread_restrictions.h"
 #include "chrome/browser/printing/print_job_worker.h"
 
 namespace printing {
@@ -96,6 +97,10 @@ void PrinterQuery::GetSettings(GetSettingsAskParam ask_user_for_settings,
 
 void PrinterQuery::StopWorker() {
   if (worker_.get()) {
+    // http://crbug.com/66082: We're blocking on the PrinterQuery's worker
+    // thread.  It's not clear to me if this may result in blocking the current
+    // thread for an unacceptable time.  We should probably fix it.
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
     worker_->Stop();
     worker_.reset();
   }