webgl: Replace query task observer with a posted task

third_party/WebKit/Source/modules/webgl/WebGLQuery.h

Index: third_party/WebKit/Source/modules/webgl/WebGLQuery.h
diff --git a/third_party/WebKit/Source/modules/webgl/WebGLQuery.h b/third_party/WebKit/Source/modules/webgl/WebGLQuery.h
index 2c98144b4638249055b4491e35a3db753c8593ff..cedbee94d42dea35deedac0b57903275c24e69cf 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGLQuery.h
+++ b/third_party/WebKit/Source/modules/webgl/WebGLQuery.h
@@ -6,6 +6,7 @@
 #define WebGLQuery_h
 
 #include "modules/webgl/WebGLSharedPlatform3DObject.h"
+#include "platform/scheduler/CancellableTaskFactory.h"
 
 namespace gpu {
 namespace gles2 {
@@ -16,8 +17,9 @@ class GLES2Interface;
 namespace blink {
 
 class WebGL2RenderingContextBase;
+class WebTaskRunner;
 
-class WebGLQuery : public WebGLSharedPlatform3DObject, public WebThread::TaskObserver {
+class WebGLQuery : public WebGLSharedPlatform3DObject {
     DEFINE_WRAPPERTYPEINFO();
 public:
     ~WebGLQuery() override;
@@ -42,19 +44,17 @@ protected:
 private:
     bool isQuery() const override { return true; }
 
-    void registerTaskObserver();
-    void unregisterTaskObserver();
-
-    // TaskObserver implementation.
-    void didProcessTask() override;
-    void willProcessTask() override { }
+    void scheduleAllowAvailabilityUpdate();
+    void allowAvailabilityUpdate();
 
     GLenum m_target;
 
-    bool m_taskObserverRegistered;
     bool m_canUpdateAvailability;
     bool m_queryResultAvailable;
     GLuint m_queryResult;
+
+    std::unique_ptr<WebTaskRunner> m_taskRunner;
+    std::unique_ptr<CancellableTaskFactory> m_cancellableTaskFactory;
 };
 
 } // namespace blink