TabCapture: enforce active refresh if there is un-sampled compositor update

media/capture/content/video_capture_oracle_unittest.cc

Index: media/capture/content/video_capture_oracle_unittest.cc
diff --git a/media/capture/content/video_capture_oracle_unittest.cc b/media/capture/content/video_capture_oracle_unittest.cc
index fcfa40c469178c924ea86f65e432190c7341e994..9b110024fb491599bb782d05fc37916553e6b0cc 100644
--- a/media/capture/content/video_capture_oracle_unittest.cc
+++ b/media/capture/content/video_capture_oracle_unittest.cc
@@ -350,6 +350,42 @@ TEST(VideoCaptureOracleTest, DoesNotRapidlyChangeCaptureSize) {
   }
 }
 
+// Tests that un-sampled compositor update event will fail the next passive
+// refresh request to force an active refresh.

[miu, 2017/03/24 21:19:39]

nit: s/refresh request to force/refresh request, forcing/

[braveyao, 2017/03/24 23:12:27]

Done.

+TEST(VideoCaptureOracleTest, EnforceActiveRefreshForUnsampledCompositorUpdate) {
+  const gfx::Rect damage_rect(Get720pSize());
+  const base::TimeDelta event_increment = Get30HzPeriod() * 2;
+  const base::TimeDelta short_event_increment = Get30HzPeriod() / 4;
+
+  VideoCaptureOracle oracle(Get30HzPeriod(), Get720pSize(),
+                            media::RESOLUTION_POLICY_FIXED_RESOLUTION, false);
+
+  base::TimeTicks t = InitialTestTimeTicks();
+  int last_frame_number;
+  base::TimeTicks ignored;
+
+  // CompositorUpdate is sampled normally.
+  t += event_increment;
+  ASSERT_TRUE(oracle.ObserveEventAndDecideCapture(
+      VideoCaptureOracle::kCompositorUpdate, damage_rect, t));
+  last_frame_number = oracle.next_frame_number();
+  oracle.RecordCapture(0.0);
+  ASSERT_TRUE(oracle.CompleteCapture(last_frame_number, true, &ignored));
+
+  // Next CompositorUpdate comes too soon and won't be sampled.
+  t += short_event_increment;
+  ASSERT_FALSE(oracle.ObserveEventAndDecideCapture(
+      VideoCaptureOracle::kCompositorUpdate, damage_rect, t));
+
+  // Then the next valid PassiveRefreshRequest will fail to enforce an
+  // ActiveRefreshRequest to capture the updated content.
+  t += event_increment;
+  ASSERT_FALSE(oracle.ObserveEventAndDecideCapture(
+      VideoCaptureOracle::kPassiveRefreshRequest, damage_rect, t));
+  ASSERT_TRUE(oracle.ObserveEventAndDecideCapture(
+      VideoCaptureOracle::kActiveRefreshRequest, damage_rect, t));
+}
+
 namespace {
 
 // Tests that VideoCaptureOracle can auto-throttle by stepping the capture size