experiment with -Wimplicit-fallthrough

media/base/video_frame.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/base/video_frame.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 283 matching lines @@
     case VideoFrame::I420: {
       switch (plane) {
         case VideoFrame::kYPlane:
           return area;
         case VideoFrame::kUPlane:
         case VideoFrame::kVPlane:
           return area / 4;
         default:
           break;
       }
+      break;
     }
     case VideoFrame::YV12A: {
       switch (plane) {
         case VideoFrame::kYPlane:
         case VideoFrame::kAPlane:
           return area;
         case VideoFrame::kUPlane:
         case VideoFrame::kVPlane:
           return area / 4;
         default:
           break;
       }
+      break;
     }
     case VideoFrame::YV16: {
       switch (plane) {
         case VideoFrame::kYPlane:
           return area;
         case VideoFrame::kUPlane:
         case VideoFrame::kVPlane:
           return area / 2;
         default:
           break;
       }
+      break;
     }
     case VideoFrame::UNKNOWN:
     case VideoFrame::NATIVE_TEXTURE:
     case VideoFrame::HISTOGRAM_MAX:
 #if defined(VIDEO_HOLE)
     case VideoFrame::HOLE:
 #endif  // defined(VIDEO_HOLE)
       break;
   }
   NOTREACHED() << "Unsupported video frame format/plane: "
@@ skipping 94 matching lines @@
 }
 
 int VideoFrame::row_bytes(size_t plane) const {
   DCHECK(IsValidPlane(plane));
   int width = coded_size_.width();
   switch (format_) {
     // Planar, 8bpp.
     case YV12A:
       if (plane == kAPlane)
         return width;
-    // Fallthrough.
+    FALLTHROUGH_INTENDED;
     case YV12:
     case YV16:
     case I420:
     case YV12J:
       if (plane == kYPlane)
         return width;
       return RoundUp(width, 2) / 2;
 
     default:
       break;
   }
 
   // Intentionally leave out non-production formats.
   NOTREACHED() << "Unsupported video frame format: " << format_;
   return 0;
 }
 
 int VideoFrame::rows(size_t plane) const {
   DCHECK(IsValidPlane(plane));
   int height = coded_size_.height();
   switch (format_) {
     case YV16:
       return height;
 
     case YV12A:
       if (plane == kAPlane)
         return height;
-    // Fallthrough.
+      FALLTHROUGH_INTENDED;
     case YV12:
     case I420:
       if (plane == kYPlane)
         return height;
       return RoundUp(height, 2) / 2;
 
     default:
       break;
   }
 
@@ skipping 40 matching lines @@
     : mailbox_(mailbox),
       sync_point_(sync_point),
       release_callback_(release_callback) {}
 
 VideoFrame::MailboxHolder::~MailboxHolder() {
   if (!release_callback_.is_null())
     release_callback_.Run(sync_point_);
 }
 
 }  // namespace media