scheduler: Implement task observers

content/renderer/renderer_blink_platform_impl.cc

Index: content/renderer/renderer_blink_platform_impl.cc
diff --git a/content/renderer/renderer_blink_platform_impl.cc b/content/renderer/renderer_blink_platform_impl.cc
index 83a6ece709ccb9fd2e3ac3db0120b0104f880078..9c7f294fd997515a57b1d3686574ae500a60aa30 100644
--- a/content/renderer/renderer_blink_platform_impl.cc
+++ b/content/renderer/renderer_blink_platform_impl.cc
@@ -52,6 +52,7 @@
 #include "content/renderer/renderer_clipboard_delegate.h"
 #include "content/renderer/scheduler/renderer_scheduler.h"
 #include "content/renderer/scheduler/web_scheduler_impl.h"
+#include "content/renderer/scheduler/webthread_impl_for_scheduler.h"
 #include "content/renderer/screen_orientation/screen_orientation_observer.h"
 #include "content/renderer/webclipboard_impl.h"
 #include "content/renderer/webgraphicscontext3d_provider_impl.h"
@@ -231,6 +232,7 @@ RendererBlinkPlatformImpl::RendererBlinkPlatformImpl(
     RendererScheduler* renderer_scheduler)
     : BlinkPlatformImpl(renderer_scheduler->DefaultTaskRunner()),
       web_scheduler_(new WebSchedulerImpl(renderer_scheduler)),
+      main_thread_(new WebThreadImplForScheduler(renderer_scheduler)),
       clipboard_delegate_(new RendererClipboardDelegate),
       clipboard_(new WebClipboardImpl(clipboard_delegate_.get())),
       mime_registry_(new RendererBlinkPlatformImpl::MimeRegistry),
@@ -266,6 +268,12 @@ blink::WebScheduler* RendererBlinkPlatformImpl::scheduler() {
   return web_scheduler_.get();
 }
 
+blink::WebThread* RendererBlinkPlatformImpl::currentThread() {
+  if (main_thread_->isCurrentThread())
+    return main_thread_.get();
+  return BlinkPlatformImpl::currentThread();
+}
+
 blink::WebClipboard* RendererBlinkPlatformImpl::clipboard() {
   blink::WebClipboard* clipboard =
       GetContentClient()->renderer()->OverrideWebClipboard();