Adding a SetRAILMode API.

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index a58e66091d405f95a46fa00d722fe53e00dd6101..3ace224471eef8f347f330d80a48a27a4343d7b2 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -5357,6 +5357,17 @@ struct JitCodeEvent {
 };
 
 /**
+ * Option flags passed to the SetRAILMode function.
+ */
+enum RAILMode {
+  PERFORMANCE_DEFAULT,

[rmcilroy, 2016/05/20 10:29:00]

Could you add a comment to each of these describing the expectation of when it
would be set.

[Sami, 2016/05/20 10:37:32]

+1, a short snippet per state would be useful -- especially if there are
downsides to sticking in a particular mode for too long.

[Hannes Payer (out of office), 2016/05/20 11:02:41]

Done.

+  PERFORMANCE_RESPONSE,
+  PERFORMANCE_ANIMATION,
+  PERFORMANCE_IDLE,
+  PERFORMANCE_LOAD
+};
+
+/**
  * Option flags passed to the SetJitCodeEventHandler function.
  */
 enum JitCodeEventOptions {
@@ -6158,6 +6169,13 @@ class V8_EXPORT Isolate {
   void IsolateInBackgroundNotification();
 
   /**
+   * Optional notification to tell V8 the current performance requirements
+   * of the embedder based on RAIL.
+   * V8 uses these notifications to guide heuristics.
+   */
+  void SetRAILMode(RAILMode rail_mode);
+
+  /**
    * Allows the host application to provide the address of a function that is
    * notified each time code is added, moved or removed.
    *