Refactor QR scanner view files to subclass from Scanner View

Architecture:
Superclass - scannerView
Subclasses - qrScannerView

- Shift the video preview view and preview overlay view to shared 'scanner' directory.

Bug: 990744
Change-Id: Ib81957f80d18b205865d9e4e6390c4ca56e4cf77
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1736889
Commit-Queue: Tanisha Mandre <tanishamandre@google.com>
Reviewed-by: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#688141}

• ios/chrome/app/strings/ios_strings.grd[diff]
• ios/chrome/browser/ui/qr_scanner/BUILD.gn[diff]
• ios/chrome/browser/ui/qr_scanner/qr_scanner_view.h[diff]
• ios/chrome/browser/ui/qr_scanner/qr_scanner_view.mm[diff]
• ios/chrome/browser/ui/qr_scanner/qr_scanner_view_controller.h[diff]
• ios/chrome/browser/ui/qr_scanner/qr_scanner_view_controller.mm[diff]
• ios/chrome/browser/ui/qr_scanner/qr_scanner_view_controller_egtest.mm[diff]
• ios/chrome/browser/ui/qr_scanner/resources/BUILD.gn[Deleted - diff]
• ios/chrome/browser/ui/scanner/BUILD.gn[Added - diff]
• ios/chrome/browser/ui/scanner/preview_overlay_view.h[Renamed from ios/chrome/browser/ui/qr_scanner/preview_overlay_view.h - diff]
• ios/chrome/browser/ui/scanner/preview_overlay_view.mm[Renamed from ios/chrome/browser/ui/qr_scanner/preview_overlay_view.mm - diff]
• ios/chrome/browser/ui/scanner/resources/BUILD.gn[Added - diff]
• ios/chrome/browser/ui/scanner/resources/QRScanner.xcassets/Contents.json[Renamed from ios/chrome/browser/ui/qr_scanner/resources/QRScanner.xcassets/Contents.json - diff]
• ios/chrome/browser/ui/scanner/resources/scanner_torch_off.imageset/Contents.json[Renamed from ios/chrome/browser/ui/qr_scanner/resources/qr_scanner_torch_off.imageset/Contents.json - diff]
• ios/chrome/browser/ui/scanner/resources/scanner_torch_off.imageset/torch_off.png[Renamed from ios/chrome/browser/ui/qr_scanner/resources/qr_scanner_torch_off.imageset/torch_off.png - diff]
• ios/chrome/browser/ui/scanner/resources/scanner_torch_off.imageset/torch_off@2x.png[Renamed from ios/chrome/browser/ui/qr_scanner/resources/qr_scanner_torch_off.imageset/torch_off@2x.png - diff]
• ios/chrome/browser/ui/scanner/resources/scanner_torch_off.imageset/torch_off@3x.png[Renamed from ios/chrome/browser/ui/qr_scanner/resources/qr_scanner_torch_off.imageset/torch_off@3x.png - diff]
• ios/chrome/browser/ui/scanner/resources/scanner_torch_on.imageset/Contents.json[Renamed from ios/chrome/browser/ui/qr_scanner/resources/qr_scanner_torch_on.imageset/Contents.json - diff]
• ios/chrome/browser/ui/scanner/resources/scanner_torch_on.imageset/torch_on.png[Renamed from ios/chrome/browser/ui/qr_scanner/resources/qr_scanner_torch_on.imageset/torch_on.png - diff]
• ios/chrome/browser/ui/scanner/resources/scanner_torch_on.imageset/torch_on@2x.png[Renamed from ios/chrome/browser/ui/qr_scanner/resources/qr_scanner_torch_on.imageset/torch_on@2x.png - diff]
• ios/chrome/browser/ui/scanner/resources/scanner_torch_on.imageset/torch_on@3x.png[Renamed from ios/chrome/browser/ui/qr_scanner/resources/qr_scanner_torch_on.imageset/torch_on@3x.png - diff]
• ios/chrome/browser/ui/scanner/scanner_view.h[Added - diff]
• ios/chrome/browser/ui/scanner/scanner_view.mm[Added - diff]
• ios/chrome/browser/ui/scanner/video_preview_view.h[Renamed from ios/chrome/browser/ui/qr_scanner/video_preview_view.h - diff]
• ios/chrome/browser/ui/scanner/video_preview_view.mm[Renamed from ios/chrome/browser/ui/qr_scanner/video_preview_view.mm - diff]