Fix 'Use Camera' button crash.

-Normalise the 'region of interest' rectangle to make it usable by the Vision request.
- Retrieve the rect from the Preview Overlay View to ensure it is only being received from view related files and doesn't need the camera connection to be setup.

Bug:1005216

Change-Id: I2d66fe77dee961ee44387bd42aea7df72f1cf48d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1810531
Commit-Queue: Tanisha Mandre <tanishamandre@google.com>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#698452}

ios/chrome/browser/ui/scanner/scanner_view.h

@@ -65,6 +65,9 @@
 // Rounds the parameters of the preview layer's transform.
 - (void)finishPreviewRotation;
 
+// Returns the normalised rectangle of interest required for the Vision request.
+- (CGRect)viewportRegionOfInterest;
+
 // Returns the rectangle in camera coordinates in which items should be
 // recognized.
 - (CGRect)viewportRectOfInterest;

ios/chrome/browser/ui/scanner/scanner_view.mm

@@ -148,6 +148,10 @@ const CGFloat kFlashDuration = 0.5;
   [_previewView setTransform:rotation];
 }
 
+- (CGRect)viewportRegionOfInterest {
+  return [_previewView viewportRegionOfInterest];
+}
+
 - (CGRect)viewportRectOfInterest {
   return [_previewView viewportRectOfInterest];
 }

ios/chrome/browser/ui/scanner/video_preview_view.h

@@ -23,6 +23,9 @@
 // Returns the VideoPreviewView's layer cast to AVCaptureVideoPreviewLayer.
 - (AVCaptureVideoPreviewLayer*)previewLayer;
 
+// Returns the normalised rectangle of interest required for the Vision request.
+- (CGRect)viewportRegionOfInterest;
+
 // Returns the rectangle in camera coordinates in which codes should be
 // recognized.
 - (CGRect)viewportRectOfInterest;

ios/chrome/browser/ui/scanner/video_preview_view.mm

@@ -38,6 +38,19 @@
   return base::mac::ObjCCastStrict<AVCaptureVideoPreviewLayer>([self layer]);
 }
 
+- (CGRect)viewportRegionOfInterest {
+  CGRect rect = CGRectMakeCenteredRectInFrame(self.frame.size, _viewportSize);
+  CGFloat x = rect.origin.x / self.frame.size.width;
+  CGFloat y = rect.origin.y / self.frame.size.height;
+
+  CGFloat width = rect.size.width / self.frame.size.width;
+  CGFloat height = rect.size.height / self.frame.size.height;
+
+  // Vision region of interest measures the frame size from the lower left
+  // corner so reverse x & y, reverse width & height.
+  return CGRectMake(y, x, height, width);
+}
+
 - (CGRect)viewportRectOfInterest {
   DCHECK(CGPointEqualToPoint(self.frame.origin, CGPointZero));
   CGRect viewportRect =

ios/chrome/browser/ui/settings/credit_card_scanner/credit_card_scanner_view_controller.mm

@@ -77,7 +77,7 @@ NSString* const kCreditCardScannerViewID = @"kCreditCardScannerViewID";
 
 - (void)viewDidLayoutSubviews {
   [super viewDidLayoutSubviews];
-  self.creditCardViewport = [self.scannerView viewportRectOfInterest];
+  self.creditCardViewport = [self.scannerView viewportRegionOfInterest];
 }
 
 #pragma mark - ScannerViewController