Reland r17877 - Introduce a v8::Platform class that bundles embedder callbacks

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index df82352703664bd2019d1fb3727df7d638af9cbc..1bd4847cb96594d7d28303bd77fc49846380c97b 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -105,6 +105,7 @@ class NumberObject;
 class Object;
 class ObjectOperationDescriptor;
 class ObjectTemplate;
+class Platform;
 class Primitive;
 class RawOperationDescriptor;
 class Signature;
@@ -4798,6 +4799,18 @@ class V8_EXPORT V8 {
    */
   static bool InitializeICU();
 
+  /**
+   * Sets the v8::Platform to use. This should be invoked before V8 is
+   * initialized.
+   */
+  static void InitializePlatform(Platform* platform);
+
+  /**
+   * Clears all references to the v8::Platform. This should be invoked after
+   * V8 was disposed.
+   */
+  static void ShutdownPlatform();
+
  private:
   V8();