Effective revert of "Allow one undrawn frame in ShouldSendBeginFrame"

This effectively reverts commit
7e8de286.

Reason for revert: Testing whether this change was responsible for
the latency regression seen in crbug.com/959048.

This isn't a true revert, as that CL no longer reverts cleanly, but this
restores our previous behavior.

Bug: 935630, 959048
Change-Id: Iefb4bd614b5802cfa24a8cb459e62842cfa6d4e8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1698629
Auto-Submit: Eric Karl <ericrk@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Eric Karl <ericrk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683450}

components/viz/service/display/display_unittest.cc

@@ -3409,9 +3409,12 @@ TEST_F(DisplayTest, BeginFrameThrottling) {
     EXPECT_TRUE(ShouldSendBeginFrame(support_.get(), frame_time));
     UpdateBeginFrameTime(support_.get(), frame_time);
     submit_frame();
-    // Immediately after submitting frame, because there is presentation
-    // feedback queued up, ShouldSendBeginFrame should always return true.
-    EXPECT_TRUE(ShouldSendBeginFrame(support_.get(), frame_time));
+    // If we've submitted more than one frame without drawing, there will
+    // always be presentation feedback so ShouldSendBeginFrame should always
+    // return true.
+    if (i > 0)
+      EXPECT_TRUE(ShouldSendBeginFrame(support_.get(), frame_time));
+
     // Clear the presentation feedbacks.
     UpdateBeginFrameTime(support_.get(), frame_time);
   }
@@ -3564,9 +3567,11 @@ TEST_F(DisplayTest, DontThrottleWhenParentBlocked) {
     UpdateBeginFrameTime(sub_support.get(), frame_time);
     sub_support->SubmitCompositorFrame(sub_local_surface_id,
                                        MakeDefaultCompositorFrame());
-    // Immediately after submitting frame, because there is presentation
-    // feedback queued up, ShouldSendBeginFrame should always return true.
-    EXPECT_TRUE(ShouldSendBeginFrame(sub_support.get(), frame_time));
+    // If we've submitted more than one frame without drawing, there will
+    // always be presentation feedback so ShouldSendBeginFrame should always
+    // return true.
+    if (i > 0)
+      EXPECT_TRUE(ShouldSendBeginFrame(support_.get(), frame_time));
     // Clear the presentation feedbacks.
     UpdateBeginFrameTime(sub_support.get(), frame_time);
   }

components/viz/service/frame_sinks/compositor_frame_sink_support.h

@@ -14,6 +14,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/optional.h"
 #include "base/time/time.h"
+#include "build/build_config.h"
 #include "components/viz/common/frame_sinks/begin_frame_source.h"
 #include "components/viz/common/frame_timing_details_map.h"
 #include "components/viz/common/quads/compositor_frame.h"
@@ -67,7 +68,13 @@ class VIZ_SERVICE_EXPORT CompositorFrameSinkSupport
   // exceeded, we throttle sBeginFrames to 1 per second. Limit must be at least
   // 1, as the relative ordering of renderer / browser frame submissions allows
   // us to have one outstanding undrawn frame under normal operation.
+#if defined(OS_ANDROID)
+  // TODO(ericrk): Revert this. Setting to 0 temporarily to test the impact of
+  // this change on a latency regression. See https://crbug.com/959048
+  static constexpr uint32_t kUndrawnFrameLimit = 0;
+#else
   static constexpr uint32_t kUndrawnFrameLimit = 3;
+#endif
 
   CompositorFrameSinkSupport(mojom::CompositorFrameSinkClient* client,
                              FrameSinkManagerImpl* frame_sink_manager,