Wire up windowless plugins. Mostly Mac related, some cross

chrome/plugin/plugin_main.cc

Index: chrome/plugin/plugin_main.cc
===================================================================
--- chrome/plugin/plugin_main.cc	(revision 20445)
+++ chrome/plugin/plugin_main.cc	(working copy)
@@ -27,6 +27,47 @@
 #include "base/global_descriptors_posix.h"
 #endif
 
+#if defined(OS_MACOSX)
+
+// To support Mac NPAPI plugins that use the Carbon event model (i.e., most
+// shipping plugins for MacOS X 10.5 and earlier), we need some way for the
+// Carbon event dispatcher to run, even though the plugin host process itself
+// does not use Carbon events.  Rather than give control to the standard
+// Carbon event loop, we schedule a periodic task on the main thread which
+// empties the Carbon event queue every 20ms (chosen to match how often Safari
+// does the equivalent operation).  This allows plugins to receive idle events
+// and schedule Carbon timers without swamping the CPU.  If, in the future,
+// we remove support for the Carbon event model and only support the Cocoa
+// event model, this can be removed.  Note that this approach does not install
+// standard application event handlers for the menubar, AppleEvents, and so on.
+// This is intentional, since the plugin process is not actually an application
+// with its own UI elements--all rendering and event handling happens via IPC
+// to the renderer process which invoked it.
+
+namespace {
+
+const int kPluginUpdateIntervalMs = 20; // 20ms = 50Hz
+
+void PluginCarbonEventTask() {
+  EventRef theEvent;
+  EventTargetRef theTarget;
+
+  theTarget = GetEventDispatcherTarget();
+
+  // Dispatch any pending events. but do not block if there are no events.
+  while (ReceiveNextEvent(0, NULL, kEventDurationNoWait,
+                          true, &theEvent) == noErr) {
+    SendEventToEventTarget (theEvent, theTarget);
+    ReleaseEvent(theEvent);
+  }
+
+  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+      NewRunnableFunction(PluginCarbonEventTask), kPluginUpdateIntervalMs);
+}
+
+}
+#endif
+
 // main() routine for running as the plugin process.
 int PluginMain(const MainFunctionParams& parameters) {
   // The main thread of the plugin services IO.
@@ -37,9 +78,9 @@
   // Initialize the SystemMonitor
   base::SystemMonitor::Start();
 
-#if defined(OS_WIN)
   const CommandLine& parsed_command_line = parameters.command_line_;
 
+#if defined(OS_WIN)
   sandbox::TargetServices* target_services =
       parameters.sandbox_info_.TargetServices();
 
@@ -59,17 +100,33 @@
       DCHECK(sandbox_test_module);
     }
   }
-
+#endif
   if (parsed_command_line.HasSwitch(switches::kPluginStartupDialog)) {
+#if defined(OS_WIN)
     std::wstring title = chrome::kBrowserAppName;
     title += L" plugin";  // makes attaching to process easier
     win_util::MessageBox(NULL, L"plugin starting...", title,
                          MB_OK | MB_SETFOREGROUND);
-  }
+#elif defined(OS_MACOSX)
+    // TODO(playmobil): In the long term, overriding this flag doesn't seem
+    // right, either use our own flag or open a dialog we can use.
+    // This is just to ease debugging in the interim.
+    LOG(WARNING) << "Plugin ("
+    << getpid()
+    << ") paused waiting for debugger to attach @ pid";
+    pause();
 #else
   NOTIMPLEMENTED() << " non-windows startup, plugin startup dialog etc.";
 #endif
+  }
 
+#if defined(OS_MACOSX)
+  // Spin off a consumer for the native (Carbon) event stream so
+  // that plugin timers, event handlers, etc. will work properly.
+  MessageLoop::current()->PostDelayedTask(FROM_HERE,
+      NewRunnableFunction(PluginCarbonEventTask), kPluginUpdateIntervalMs);
+#endif
+
   {
     ChildProcess plugin_process(new PluginThread());
 #if defined(OS_WIN)