viz: Fix FindLatestSurfaceUpTo when there is conflict

The condition used in the binary search was wrong. Fixed it and added
a unit test.

Bug: 1000868
Change-Id: Iaf4af1bdfdb88db1082bfae89a3783faed860934
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1800743
Auto-Submit: Saman Sami <samans@chromium.org>
Commit-Queue: Jonathan Ross <jonross@chromium.org>
Reviewed-by: Jonathan Ross <jonross@chromium.org>
Cr-Commit-Position: refs/heads/master@{#696170}

components/viz/service/frame_sinks/surface_synchronization_unittest.cc

@@ -3073,6 +3073,22 @@ TEST_F(SurfaceSynchronizationTest,
   EXPECT_EQ(parent_id2, parent_support().last_activated_surface_id());
 }
 
+// Regression test for https://crbug.com/1000868. Verify that the output of
+// GetLatestInFlightSurface is correct when there is a conflict between the last
+// surface in the group and the queried SurfaceRange.
+TEST_F(SurfaceSynchronizationTest, LatestInFlightSurfaceConflict) {
+  const SurfaceId id1 = MakeSurfaceId(kParentFrameSink, 1, 1);
+  const SurfaceId id2 = MakeSurfaceId(kParentFrameSink, 2, 2);
+  const SurfaceId id3 = MakeSurfaceId(kParentFrameSink, 1, 3);
+
+  parent_support().SubmitCompositorFrame(id1.local_surface_id(),
+                                         MakeDefaultCompositorFrame());
+  parent_support().SubmitCompositorFrame(id2.local_surface_id(),
+                                         MakeDefaultCompositorFrame());
+  EXPECT_EQ(GetSurfaceForId(id1),
+            GetLatestInFlightSurface(SurfaceRange(base::nullopt, id3)));
+}
+
 // Check that if two different SurfaceIds with the same embed token are
 // embedded, viz doesn't crash. https://crbug.com/1001143
 TEST_F(SurfaceSynchronizationTest,

components/viz/service/surfaces/surface_allocation_group.cc

@@ -188,7 +188,7 @@ SurfaceAllocationGroup::FindLatestSurfaceUpTo(
 
   // If even the first surface is newer than |surface_id|, we can't find a
   // surface that is older than or equal to |surface_id|.
-  if (surfaces_[0]->surface_id().IsNewerThan(surface_id))
+  if (!surface_id.IsSameOrNewerThan(surfaces_[0]->surface_id()))
     return surfaces_.end();
 
   // Perform a binary search the find the latest surface that is older than or
@@ -197,12 +197,13 @@ SurfaceAllocationGroup::FindLatestSurfaceUpTo(
   int end = surfaces_.size();
   while (end - begin > 1) {
     int avg = (begin + end) / 2;
-    if (surfaces_[avg]->surface_id().IsNewerThan(surface_id))
+    if (!surface_id.IsSameOrNewerThan(surfaces_[avg]->surface_id()))
       end = avg;
     else
       begin = avg;
   }
 
+  DCHECK(surface_id.IsSameOrNewerThan(surfaces_[begin]->surface_id()));
   return surfaces_.begin() + begin;
 }