Move device_motion_hardware_buffer.h to device_orientation/ subdirectory.

The device_motion_hardware_buffer.h should be in the content/common/device_orientation/
subdirectory where all other related files are located.

BUG=

Review URL: https://codereview.chromium.org/25878002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228196 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228196