Provide an iOS message pump for IO implementation.

base/message_loop.cc

Index: base/message_loop.cc
diff --git a/base/message_loop.cc b/base/message_loop.cc
index f4279935227e760f0061025a092ca477ba19b249..542802672927403a6d57f35ed65f11bc5d10d502 100644
--- a/base/message_loop.cc
+++ b/base/message_loop.cc
@@ -27,7 +27,7 @@
 #if defined(OS_MACOSX)
 #include "base/message_pump_mac.h"
 #endif
-#if defined(OS_POSIX)
+#if defined(OS_POSIX) && !defined(OS_IOS)
 #include "base/message_pump_libevent.h"
 #endif
 #if defined(OS_ANDROID)
@@ -157,6 +157,9 @@ MessageLoop::MessageLoop(Type type)
 #if defined(OS_WIN)
 #define MESSAGE_PUMP_UI new base::MessagePumpForUI()
 #define MESSAGE_PUMP_IO new base::MessagePumpForIO()
+#elif defined(OS_IOS)
+#define MESSAGE_PUMP_UI base::MessagePumpMac::Create()
+#define MESSAGE_PUMP_IO new base::MessagePumpIOSForIO()
 #elif defined(OS_MACOSX)
 #define MESSAGE_PUMP_UI base::MessagePumpMac::Create()
 #define MESSAGE_PUMP_IO new base::MessagePumpLibevent()
@@ -776,6 +779,21 @@ bool MessageLoopForIO::WaitForIOCompletion(DWORD timeout, IOHandler* filter) {
   return pump_io()->WaitForIOCompletion(timeout, filter);
 }
 
+#elif defined(OS_IOS)
+
+bool MessageLoopForIO::WatchFileDescriptor(int fd,
+                                           bool persistent,
+                                           Mode mode,
+                                           FileDescriptorWatcher *controller,
+                                           Watcher *delegate) {
+  return pump_io()->WatchFileDescriptor(
+      fd,
+      persistent,
+      mode,
+      controller,
+      delegate);
+}
+
 #elif defined(OS_POSIX) && !defined(OS_NACL)
 
 bool MessageLoopForIO::WatchFileDescriptor(int fd,
@@ -786,7 +804,7 @@ bool MessageLoopForIO::WatchFileDescriptor(int fd,
   return pump_libevent()->WatchFileDescriptor(
       fd,
       persistent,
-      static_cast<base::MessagePumpLibevent::Mode>(mode),
+      mode,
       controller,
       delegate);
 }