Tab/Desktop Capture: Use requests instead of timer-based refreshing.

media/capture/content/video_capture_oracle.h

Index: media/capture/content/video_capture_oracle.h
diff --git a/media/capture/content/video_capture_oracle.h b/media/capture/content/video_capture_oracle.h
index 8c4f6827e582d8ed7fe5f64ce8418143ff392b78..92a63a45a9c8b58c477691bec299a27c97b4d3e8 100644
--- a/media/capture/content/video_capture_oracle.h
+++ b/media/capture/content/video_capture_oracle.h
@@ -24,19 +24,13 @@ namespace media {
 class MEDIA_EXPORT VideoCaptureOracle {
  public:
   enum Event {
-    kTimerPoll,
     kCompositorUpdate,
+    kActiveRefreshRequest,
+    kPassiveRefreshRequest,
     kMouseCursorUpdate,
     kNumEvents,
   };
 
-  enum {
-    // The recommended minimum amount of time between calls to
-    // ObserveEventAndDecideCapture() for the kTimerPoll Event type.  Anything
-    // lower than this isn't harmful, just wasteful.
-    kMinTimerPollPeriodMillis = 125,  // 8 FPS
-  };
-
   VideoCaptureOracle(base::TimeDelta min_capture_period,
                      const gfx::Size& max_frame_size,
                      media::ResolutionChangePolicy resolution_change_policy,
@@ -104,6 +98,10 @@ class MEDIA_EXPORT VideoCaptureOracle {
     return last_time_animation_was_detected_;
   }
 
+  // Returns a NUL-terminated string containing a short, human-readable form of
+  // |event|.
+  static const char* EventAsString(Event event);
+
  private:
   // Retrieve/Assign a frame timestamp by capture |frame_number|.  Only valid
   // when IsFrameInRecentHistory(frame_number) returns true.