ImageCapture: support exposure mode configuration

media/mojo/interfaces/image_capture.mojom

Index: media/mojo/interfaces/image_capture.mojom
diff --git a/media/mojo/interfaces/image_capture.mojom b/media/mojo/interfaces/image_capture.mojom
index 098ded2111aa49f1aa835e05f7e860d0a7b49c9b..fe7c08a998092d6f9758c5170efa14eb67f01a81 100644
--- a/media/mojo/interfaces/image_capture.mojom
+++ b/media/mojo/interfaces/image_capture.mojom
@@ -13,8 +13,8 @@ struct Range {
   uint32 current;
 };
 
-// https://w3c.github.io/mediacapture-image/#idl-def-FocusMode
-enum FocusMode { UNAVAILABLE, MANUAL, SINGLE_SHOT, CONTINUOUS };
+// https://w3c.github.io/mediacapture-image/#idl-def-MeteringMode
+enum MeteringMode { UNAVAILABLE, MANUAL, SINGLE_SHOT, CONTINUOUS };
 
 // Equivalent to idl PhotoCapabilities,
 // https://w3c.github.io/mediacapture-image/#photocapabilities
@@ -23,7 +23,8 @@ struct PhotoCapabilities {
   Range height;
   Range width;
   Range zoom;
-  FocusMode focus_mode;
+  MeteringMode focus_mode;
+  MeteringMode exposure_mode;
 };
 
 // Equivalent to idl Point2D.
@@ -44,7 +45,9 @@ struct PhotoSettings {
   bool has_height;
   uint32 height;
   bool has_focus_mode;
-  FocusMode focus_mode;
+  MeteringMode focus_mode;
+  bool has_exposure_mode;
+  MeteringMode exposure_mode;
   array<Point2D> points_of_interest;
 };