Work on getting things built with -Wimplicit-fallthrough. This CL was uploaded by git cl split.

Bug: 177475
R=miu@chromium.org

Change-Id: I7aa7196b1b325b0741e6c7bb60822ac6d59dc295
Reviewed-on: https://chromium-review.googlesource.com/889780Reviewed-by: Yuri Wiitala <miu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532127}

media/cast/net/rtcp/receiver_rtcp_event_subscriber.cc

@@ -36,6 +36,7 @@ void ReceiverRtcpEventSubscriber::OnReceiveFrameEvent(
     switch (frame_event.type) {
       case FRAME_PLAYOUT:
         rtcp_event.delay_delta = frame_event.delay_delta;
+        FALLTHROUGH;
       case FRAME_ACK_SENT:
       case FRAME_DECODED:
         rtcp_event.type = frame_event.type;

media/cast/sender/external_video_encoder.cc

@@ -687,7 +687,7 @@ void ExternalVideoEncoder::OnCreateVideoEncodeAccelerator(
       break;
     case CODEC_VIDEO_FAKE:
       NOTREACHED() << "Fake software video encoder cannot be external";
-      // ...flow through to next case...
+      FALLTHROUGH;
     default:
       cast_environment_->PostTask(
         CastEnvironment::MAIN,

media/cast/sender/performance_metrics_overlay.cc

@@ -180,7 +180,7 @@ void RenderLineOfText(const std::string& line, int top, VideoFrame* frame) {
       case '+':
         DivergePixels(gfx::Rect(1, 1, 1, 1), p_ul, stride);
         DivergePixels(gfx::Rect(1, 3, 1, 1), p_ul, stride);
-        // ...fall through...
+        FALLTHROUGH;
       case '-':
         DivergePixels(gfx::Rect(0, 2, 3, 1), p_ul, stride);
         break;