experiment with -Wimplicit-fallthrough

media/base/video_frame.cc

Index: media/base/video_frame.cc
diff --git a/media/base/video_frame.cc b/media/base/video_frame.cc
index 8a4eb3cce2b62f57daa5f4ee6dcf961157806a16..1929563588730155977fffbee40df09ee2024b76 100644
--- a/media/base/video_frame.cc
+++ b/media/base/video_frame.cc
@@ -301,6 +301,7 @@ size_t VideoFrame::PlaneAllocationSize(Format format,
         default:
           break;
       }
+      break;
     }
     case VideoFrame::YV12A: {
       switch (plane) {
@@ -313,6 +314,7 @@ size_t VideoFrame::PlaneAllocationSize(Format format,
         default:
           break;
       }
+      break;
     }
     case VideoFrame::YV16: {
       switch (plane) {
@@ -324,6 +326,7 @@ size_t VideoFrame::PlaneAllocationSize(Format format,
         default:
           break;
       }
+      break;
     }
     case VideoFrame::UNKNOWN:
     case VideoFrame::NATIVE_TEXTURE:
@@ -438,7 +441,7 @@ int VideoFrame::row_bytes(size_t plane) const {
     case YV12A:
       if (plane == kAPlane)
         return width;
-    // Fallthrough.
+    FALLTHROUGH_INTENDED;
     case YV12:
     case YV16:
     case I420:
@@ -466,7 +469,7 @@ int VideoFrame::rows(size_t plane) const {
     case YV12A:
       if (plane == kAPlane)
         return height;
-    // Fallthrough.
+      FALLTHROUGH_INTENDED;
     case YV12:
     case I420:
       if (plane == kYPlane)