Add plumbing for platform based Device Motion testing.

webkit/support/webkit_support.h

Index: webkit/support/webkit_support.h
diff --git a/webkit/support/webkit_support.h b/webkit/support/webkit_support.h
index 96fbdd1c8d678f02cebb215695e5bdfb2b7b9712..0f8c8015d03e2b20a47af0efba42a9b1a1f102ed 100644
--- a/webkit/support/webkit_support.h
+++ b/webkit/support/webkit_support.h
@@ -26,6 +26,7 @@ namespace WebKit {
 class Platform;
 class WebApplicationCacheHost;
 class WebApplicationCacheHostClient;
+class WebDeviceMotionData;
 class WebFileSystemCallbacks;
 class WebFrame;
 class WebGamepads;
@@ -250,6 +251,10 @@ void EnableWebCoreLogChannels(const std::string& channels);
 
 void SetGamepadData(const WebKit::WebGamepads& pads);
 
+// - Device Motion
+
+void SetDeviceMotionData(const WebKit::WebDeviceMotionData& data);
+
 }  // namespace webkit_support
 
 #endif  // WEBKIT_SUPPORT_WEBKIT_SUPPORT_H_