Introduce a v8::Platform class that bundles embedder callbacks

include/v8-platform.h

Index: include/v8-platform.h
diff --git a/include/v8-defaults.h b/include/v8-platform.h
similarity index 59%
copy from include/v8-defaults.h
copy to include/v8-platform.h
index b55c07fbad86efa439d77bfd05b344c1d6864d56..cf264d60e817855e048bdc4cde0578163225fda7 100644
--- a/include/v8-defaults.h
+++ b/include/v8-platform.h
@@ -25,24 +25,51 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-#ifndef V8_V8_DEFAULTS_H_
-#define V8_V8_DEFAULTS_H_
+#ifndef V8_V8_PLATFROM_H_
+#define V8_V8_PLATFORM_H_
 
 #include "v8.h"
 
+namespace v8 {
+
 /**
- * Default configuration support for the V8 JavaScript engine.
+ * A Task represents a unit of work.
  */
-namespace v8 {
+class Task {
+ public:
+  virtual ~Task() {}
 
-V8_DEPRECATED("Use ResourceConstraints::ConfigureDefaults instead",
-    bool V8_EXPORT ConfigureResourceConstraintsForCurrentPlatform(
-        ResourceConstraints* constraints));
+  virtual void Run() = 0;
+};
+
+/**
+ * V8 Platform abstraction layer.
+ *
+ * The embedder has to provide an implementation of this interface before
+ * initializing the rest of V8.
+ */
+class Platform {
+ public:
+  /**
+   * Schedules a task to be invoked on a background thread. |task_is_slow|
+   * indicates that the task will run a long time. The Platform implementation
+   * takes ownership of |task|. There is no guarantee about order of execution
+   * of tasks wrt order of scheduling, nor is there a guarantee about the
+   * thread the task will be run on.
+   */
+  virtual void CallOnBackgroundThread(Task* task, bool task_is_slow) = 0;
 
+  /**
+   * Schedules a task to be invoked on a foreground thread wrt a specific
+   * |isolate|. Tasks posted for the same isolate should be execute in order of
+   * scheduling. The definition of "foreground" is opaque to V8.
+   */
+  virtual void CallOnForegroundThread(Isolate* isolate, Task* task) = 0;
 
-V8_DEPRECATED("Use ResourceConstraints::ConfigureDefaults instead",
-    bool V8_EXPORT SetDefaultResourceConstraintsForCurrentPlatform());
+ protected:
+  virtual ~Platform() {}
+};
 
 }  // namespace v8
 
-#endif  // V8_V8_DEFAULTS_H_
+#endif  // V8_V8_PLATFORM_H_