modules/video_coding refactorings

The main purpose was the interface-> include rename, but other files
were also moved, eliminating the "main" dir.

To avoid breaking downstream, the "interface" directories were copied
into a new "video_coding/include" dir. The old headers got pragma
warnings added about deprecation (a very short deprecation since I plan
to remove them as soon downstream is updated).

Other files also moved:
video_coding/main/source -> video_coding
video_coding/main/test -> video_coding/test

BUG=webrtc:5095
TESTED=Passing compile-trybots with --clobber flag:
git cl try --clobber --bot=win_compile_rel --bot=linux_compile_rel --bot=android_compile_rel --bot=mac_compile_rel --bot=ios_rel --bot=linux_gn_rel --bot=win_x64_gn_rel --bot=mac_x64_gn_rel --bot=android_gn_rel -m tryserver.webrtc

R=stefan@webrtc.org, tommi@webrtc.org

Review URL: https://codereview.webrtc.org/1417283007 .

Cr-Commit-Position: refs/heads/master@{#10694}
diff --git a/webrtc/modules/video_coding/media_optimization_unittest.cc b/webrtc/modules/video_coding/media_optimization_unittest.cc
new file mode 100644
index 0000000..f8bc533
--- /dev/null
+++ b/webrtc/modules/video_coding/media_optimization_unittest.cc
@@ -0,0 +1,155 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/modules/video_coding/media_optimization.h"
+#include "webrtc/system_wrappers/include/clock.h"
+
+namespace webrtc {
+namespace media_optimization {
+
+class TestMediaOptimization : public ::testing::Test {
+ protected:
+  enum {
+    kSampleRate = 90000  // RTP timestamps per second.
+  };
+
+  // Note: simulated clock starts at 1 seconds, since parts of webrtc use 0 as
+  // a special case (e.g. frame rate in media optimization).
+  TestMediaOptimization()
+      : clock_(1000),
+        media_opt_(&clock_),
+        frame_time_ms_(33),
+        next_timestamp_(0) {}
+
+  // This method mimics what happens in VideoSender::AddVideoFrame.
+  void AddFrameAndAdvanceTime(uint32_t bitrate_bps, bool expect_frame_drop) {
+    bool frame_dropped = media_opt_.DropFrame();
+    EXPECT_EQ(expect_frame_drop, frame_dropped);
+    if (!frame_dropped) {
+      size_t bytes_per_frame = bitrate_bps * frame_time_ms_ / (8 * 1000);
+      EncodedImage encoded_image;
+      encoded_image._length = bytes_per_frame;
+      encoded_image._timeStamp = next_timestamp_;
+      encoded_image._frameType = kVideoFrameKey;
+      ASSERT_EQ(VCM_OK, media_opt_.UpdateWithEncodedData(encoded_image));
+    }
+    next_timestamp_ += frame_time_ms_ * kSampleRate / 1000;
+    clock_.AdvanceTimeMilliseconds(frame_time_ms_);
+  }
+
+  SimulatedClock clock_;
+  MediaOptimization media_opt_;
+  int frame_time_ms_;
+  uint32_t next_timestamp_;
+};
+
+
+TEST_F(TestMediaOptimization, VerifyMuting) {
+  // Enable video suspension with these limits.
+  // Suspend the video when the rate is below 50 kbps and resume when it gets
+  // above 50 + 10 kbps again.
+  const uint32_t kThresholdBps = 50000;
+  const uint32_t kWindowBps = 10000;
+  media_opt_.SuspendBelowMinBitrate(kThresholdBps, kWindowBps);
+
+  // The video should not be suspended from the start.
+  EXPECT_FALSE(media_opt_.IsVideoSuspended());
+
+  uint32_t target_bitrate_kbps = 100;
+  media_opt_.SetTargetRates(target_bitrate_kbps * 1000,
+                            0,    // Lossrate.
+                            100,  // RTT in ms.
+                            nullptr, nullptr);
+  media_opt_.EnableFrameDropper(true);
+  for (int time = 0; time < 2000; time += frame_time_ms_) {
+    ASSERT_NO_FATAL_FAILURE(AddFrameAndAdvanceTime(target_bitrate_kbps, false));
+  }
+
+  // Set the target rate below the limit for muting.
+  media_opt_.SetTargetRates(kThresholdBps - 1000,
+                            0,    // Lossrate.
+                            100,  // RTT in ms.
+                            nullptr, nullptr);
+  // Expect the muter to engage immediately and stay muted.
+  // Test during 2 seconds.
+  for (int time = 0; time < 2000; time += frame_time_ms_) {
+    EXPECT_TRUE(media_opt_.IsVideoSuspended());
+    ASSERT_NO_FATAL_FAILURE(AddFrameAndAdvanceTime(target_bitrate_kbps, true));
+  }
+
+  // Set the target above the limit for muting, but not above the
+  // limit + window.
+  media_opt_.SetTargetRates(kThresholdBps + 1000,
+                            0,    // Lossrate.
+                            100,  // RTT in ms.
+                            nullptr, nullptr);
+  // Expect the muter to stay muted.
+  // Test during 2 seconds.
+  for (int time = 0; time < 2000; time += frame_time_ms_) {
+    EXPECT_TRUE(media_opt_.IsVideoSuspended());
+    ASSERT_NO_FATAL_FAILURE(AddFrameAndAdvanceTime(target_bitrate_kbps, true));
+  }
+
+  // Set the target above limit + window.
+  media_opt_.SetTargetRates(kThresholdBps + kWindowBps + 1000,
+                            0,    // Lossrate.
+                            100,  // RTT in ms.
+                            nullptr, nullptr);
+  // Expect the muter to disengage immediately.
+  // Test during 2 seconds.
+  for (int time = 0; time < 2000; time += frame_time_ms_) {
+    EXPECT_FALSE(media_opt_.IsVideoSuspended());
+    ASSERT_NO_FATAL_FAILURE(
+        AddFrameAndAdvanceTime((kThresholdBps + kWindowBps) / 1000, false));
+  }
+}
+
+TEST_F(TestMediaOptimization, ProtectsUsingFecBitrateAboveCodecMax) {
+  static const int kCodecBitrateBps = 100000;
+  static const int kMaxBitrateBps = 130000;
+
+  class ProtectionCallback : public VCMProtectionCallback {
+    int ProtectionRequest(const FecProtectionParams* delta_params,
+                          const FecProtectionParams* key_params,
+                          uint32_t* sent_video_rate_bps,
+                          uint32_t* sent_nack_rate_bps,
+                          uint32_t* sent_fec_rate_bps) override {
+      *sent_video_rate_bps = kCodecBitrateBps;
+      *sent_nack_rate_bps = 0;
+      *sent_fec_rate_bps = fec_rate_bps_;
+      return 0;
+    }
+
+   public:
+    uint32_t fec_rate_bps_;
+  } protection_callback;
+
+  media_opt_.SetProtectionMethod(kFec);
+  media_opt_.SetEncodingData(kVideoCodecVP8, kCodecBitrateBps, kCodecBitrateBps,
+                             640, 480, 30, 1, 1000);
+
+  // Using 10% of codec bitrate for FEC, should still be able to use all of it.
+  protection_callback.fec_rate_bps_ = kCodecBitrateBps / 10;
+  uint32_t target_bitrate = media_opt_.SetTargetRates(
+      kMaxBitrateBps, 0, 0, &protection_callback, nullptr);
+
+  EXPECT_EQ(kCodecBitrateBps, static_cast<int>(target_bitrate));
+
+  // Using as much for codec bitrate as fec rate, new target rate should share
+  // both equally, but only be half of max (since that ceiling should be hit).
+  protection_callback.fec_rate_bps_ = kCodecBitrateBps;
+  target_bitrate = media_opt_.SetTargetRates(kMaxBitrateBps, 128, 100,
+                                             &protection_callback, nullptr);
+  EXPECT_EQ(kMaxBitrateBps / 2, static_cast<int>(target_bitrate));
+}
+
+}  // namespace media_optimization
+}  // namespace webrtc