[WIN] Fix build error of rebase.

1. Disable the warning of 4800. The warning is caused by forcing value to
   bool(performance warning).
2. gfx::NativeMenu is removed, use HMENU directly.
3. NativeMenuWin::Rebuild add one parameter: InsertionDelegate*, it can be NULL
   in our code path.
4. Upstream code move |base/file_path.h| to |base/files/file_path.h|,
   move |chrome/common/extensions/draggable_region.h| to |extensions/common/draggable_region.h|
5. |WebContents::GetNativeView| is removed. Using ->GetView()->GetNativeView();
6. |JavaScriptDialogCreator| is renamed to |JavaScriptDialogManager|
7. Several method in the base class |content::MediaObserver| of |MediaInternals|
   is removed, it's OK for us to remove it because we do nothing before.
8. Base class: |content::ContentClient| add method |GetDataResourceBytes|, so
   |content::ShellContentClient| should also override it.
Merge pull request #587 from zhchbin/nw-rebase

[WIN] Fix build error of rebase.