[piexwasm] Remove files app ColorSpace dependency

JEITA EXIF color space defines and supports two color spaces only per
the JEITA specification: sRGB and AdobeRGB1998.

The PIEX C++ returns their values as strings 'sRgb' and 'adobeRgb' so
return those values in the PiexLoaderResponse [1].

Note JEITA EXIF color space indicates the color space only. The image
does not have an embedded ICC Color Profile. A future option for piex
is to slice open the JPEG preview, insert an ICC Color Profile in the
AdobeRGB1998 case, before returning the PiexLoaderResponse.

[1] In files app, make image_request_task.js convert the value in the
PiexLoaderResponse to ColorSpace type. No change in behavior.

Bug: 1132695
Change-Id: Ifa076635dc5672a552094bf1b5fa9e69e164d9d2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2432150Reviewed-by: Trent Apted <tapted@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811128}

ui/file_manager/image_loader/image_request_task.js

@@ -336,7 +336,9 @@ ImageRequestTask.prototype.downloadOriginal_ = function(onSuccess, onFailure) {
             function(data) {
               this.request_.orientation =
                   ImageOrientation.fromExifOrientation(data.orientation);
-              this.request_.colorSpace = data.colorSpace;
+              const isAdobeRgb = data.colorSpace === 'adobeRgb';
+              this.request_.colorSpace =
+                  isAdobeRgb ? ColorSpace.ADOBE_RGB : ColorSpace.SRGB;
               this.ifd_ = data.ifd;
               this.contentType_ = data.mimeType;
               const blob = new Blob([data.thumbnail], {type: data.mimeType});

ui/file_manager/image_loader/piex_loader.js

@@ -64,7 +64,7 @@ function piexModuleFailed() {
  *  thumbnail: !ArrayBuffer,
  *  mimeType: (string|undefined),
  *  orientation: number,
- *  colorSpace: ColorSpace,
+ *  colorSpace: string,
  *  ifd: ?string
  * }}
  */
@@ -96,7 +96,8 @@ function PiexLoaderResponse(data) {
   this.orientation = data.orientation;
 
   /**
-   * @public {ColorSpace}
+   * JEITA EXIF image color space: 'sRgb' or 'adobeRgb'.
+   * @public {string}
    * @const
    */
   this.colorSpace = data.colorSpace;
@@ -179,7 +180,7 @@ function readSourceData(source) {
  *
  * @typedef {{
  *  format:number,
- *  colorSpace:ColorSpace,
+ *  colorSpace:string,
  *  orientation:number,
  *  width:?number,
  *  height:?number,
@@ -298,7 +299,7 @@ class ImageBuffer {
     if (!thumbnail) {
       return {
         thumbnail: new ArrayBuffer(0),
-        colorSpace: ColorSpace.SRGB,
+        colorSpace: 'sRgb',
         orientation: 1,
         ifd: null,
       };
@@ -338,7 +339,7 @@ class ImageBuffer {
     if (!thumbnail || thumbnail.format !== 1) {
       return {
         thumbnail: new ArrayBuffer(0),
-        colorSpace: ColorSpace.SRGB,
+        colorSpace: 'sRgb',
         orientation: 1,
         ifd: null,
       };