media/gpu/chromeos/PlatformVFPool: don't request frames with same format.

Buffer allocation is time-consuming action. This CL makes
PlatformVideoFramePool not try to allocate new buffers if all the
arguments that affects the physical layout of buffer are not changed.

Bug: 1018817
Bug: 1028406
Test: media_unittests --gtest_filter=PlatformVideoFramePool.*
Test: video_decode_accelerator_tests on Kevin and Eve

Change-Id: I3f1a2b91b0f8c762d7c16f3a873648274176a6d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1948009Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Commit-Queue: Chih-Yu Huang <akahuang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721362}

media/gpu/chromeos/platform_video_frame_pool.cc

@@ -133,16 +133,18 @@ base::Optional<GpuBufferLayout> PlatformVideoFramePool::RequestFrames(
   if (!IsSameFormat_Locked(format, coded_size)) {
     DVLOGF(4) << "The video frame format is changed. Clearing the pool.";
     free_frames_.clear();
-  }
 
-  // Create a temporary frame in order to know VideoFrameLayout that VideoFrame
-  // that will be allocated in GetFrame() has.
-  auto frame =
-      create_frame_cb_.Run(gpu_memory_buffer_factory_, format, coded_size,
-                           visible_rect_, natural_size_, base::TimeDelta());
-  if (!frame) {
-    VLOGF(1) << "Failed to create video frame";
-    return base::nullopt;
+    // Create a temporary frame in order to know VideoFrameLayout that
+    // VideoFrame that will be allocated in GetFrame() has.
+    auto frame =
+        create_frame_cb_.Run(gpu_memory_buffer_factory_, format, coded_size,
+                             visible_rect_, natural_size_, base::TimeDelta());
+    if (!frame) {
+      VLOGF(1) << "Failed to create video frame";
+      return base::nullopt;
+    }
+    frame_layout_ = GpuBufferLayout::Create(fourcc, frame->coded_size(),
+                                            frame->layout().planes());
   }
 
   // The pool might become available because of |max_num_frames_| increased.
@@ -150,8 +152,6 @@ base::Optional<GpuBufferLayout> PlatformVideoFramePool::RequestFrames(
   if (frame_available_cb_ && !IsExhausted_Locked())
     std::move(frame_available_cb_).Run();
 
-  frame_layout_ = GpuBufferLayout::Create(fourcc, frame->coded_size(),
-                                          frame->layout().planes());
   return frame_layout_;
 }
 

media/gpu/chromeos/platform_video_frame_pool_unittest.cc

@@ -179,6 +179,23 @@ TEST_F(PlatformVideoFramePoolTest, UnwrapVideoFrame) {
   EXPECT_FALSE(frame_1->IsSameDmaBufsAs(*frame_3));
 }
 
+TEST_F(PlatformVideoFramePoolTest, FormatNotChange) {
+  RequestFrames(Fourcc(Fourcc::YV12));
+  scoped_refptr<VideoFrame> frame1 = GetFrame(10);
+  DmabufId id1 = DmabufVideoFramePool::GetDmabufId(*frame1);
+
+  // Clear frame references to return the frames to the pool.
+  frame1 = nullptr;
+  task_environment_.RunUntilIdle();
+
+  // Request frame with the same format. The pool should not request new frames.
+  RequestFrames(Fourcc(Fourcc::YV12));
+
+  scoped_refptr<VideoFrame> frame2 = GetFrame(20);
+  DmabufId id2 = DmabufVideoFramePool::GetDmabufId(*frame2);
+  EXPECT_EQ(id1, id2);
+}
+
 // TODO(akahuang): Add a testcase to verify calling RequestFrames() only with
 // different |max_num_frames|.