Implement the content/renderer and content/browser part of the Device Motion API.

content/common/device_motion_messages.h

Index: content/common/device_motion_messages.h
diff --git a/content/common/device_motion_messages.h b/content/common/device_motion_messages.h
index 0d3303d4168ce79df95301c72c484e16e315cb19..b4430da8ecad3a831631f854e5d090a51eececcf 100644
--- a/content/common/device_motion_messages.h
+++ b/content/common/device_motion_messages.h
@@ -6,9 +6,27 @@
 // Multiply-included message file, hence no include guard.
 
 #include "ipc/ipc_message_macros.h"
+#include "ipc/ipc_param_traits.h"
+#include "ipc/ipc_platform_file.h"
+#include "base/shared_memory.h"
 
 #define IPC_MESSAGE_START DeviceMotionMsgStart
 
+// Messages sent from the renderer to the browser.
+
+// Asks the browser process to start polling, and return a shared memory
+// handles that will hold the data from the hardware. See
+// device_motion_hardware_buffer.h for a description of how synchronization is
+// handled. The number of Starts should match the number of Stops.
+IPC_MESSAGE_CONTROL0(DeviceMotionHostMsg_StartPolling)
+IPC_MESSAGE_CONTROL1(DeviceMotionMsg_DidStartPolling,
+                     base::SharedMemoryHandle /* handle */)
+
+IPC_MESSAGE_CONTROL0(DeviceMotionHostMsg_StopPolling)
+
+// TODO(timvolodine): remove the methods below once the Device Motion
+// is implemented.
+
 IPC_STRUCT_BEGIN(DeviceMotionMsg_Updated_Params)
   // These fields have the same meaning as in device_motion::Motion.
   IPC_STRUCT_MEMBER(bool, can_provide_acceleration_x)