Linux video capture, invoking mmap() with both READ and WRITE.

media/video/capture/linux/video_capture_device_linux.cc

Index: media/video/capture/linux/video_capture_device_linux.cc
===================================================================
--- media/video/capture/linux/video_capture_device_linux.cc	(revision 194158)
+++ media/video/capture/linux/video_capture_device_linux.cc	(working copy)
@@ -468,7 +468,9 @@
       return false;
     }
 
-    buffer_pool_[i].start = mmap(NULL, buffer.length, PROT_READ,
+    // Some devices require mmap() to be called with both READ and WRITE.
+    // See crbug.com/178582.
+    buffer_pool_[i].start = mmap(NULL, buffer.length, PROT_READ | PROT_WRITE,
                                  MAP_SHARED, device_fd_, buffer.m.offset);
     if (buffer_pool_[i].start == MAP_FAILED) {
       return false;