[piexwasm] Add BMP image color space support

Chrome and Mozilla support color space information in a BMP image [1],
when the BMP has (at least) a 108-byte BITMAPV4HEADER header [2].

Change piex-wasm BMP generation code to use a BITMAPV4HEADER. When the
preview image is sRGB, write that to the BITMAPV4HEADER. Otherwise the
image is 'adobeRgb' color space: write the RGB CIEXYZ tristimulus (the
gamut) and gamma of the AdobeRGB1988 color space, in the encoded forms
required by the BITMAPV4HEADER definition.

With this change, all images returned by peix-wasm have embedded color
space information so rendering these images in a color managed browser
like Chrome produces color-correct rendering.

[1] https://mzl.la/36S5Fm3
[2] https://bit.ly/30Iag6l

Bug: 1132695
Change-Id: Ic53d53f0a68274bb3b4f13fd31c14991d276786b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2454891Reviewed-by: Alex Danilo <adanilo@chromium.org>
Commit-Queue: Alex Danilo <adanilo@chromium.org>
Auto-Submit: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814565}

ui/file_manager/image_loader/piex_loader.js

@@ -440,7 +440,7 @@ class ImageBuffer {
     const rowStride = 3 * thumbnail.width + rowPad;
 
     // Create bitmap image.
-    const pixelDataOffset = 14 + 40;
+    const pixelDataOffset = 14 + 108;
     const fileSize = pixelDataOffset + rowStride * thumbnail.height;
     const bitmap = new DataView(new ArrayBuffer(fileSize));
 
@@ -451,8 +451,8 @@ class ImageBuffer {
     bitmap.setUint32(6, /* Reserved */ 0, true);
     bitmap.setUint32(10, pixelDataOffset, true);
 
-    // DIB BITMAPINFOHEADER 40 bytes.
-    bitmap.setUint32(14, /* HeaderSize */ 40, true);
+    // DIB BITMAPV4HEADER 108 bytes.
+    bitmap.setUint32(14, /* HeaderSize */ 108, true);
     bitmap.setInt32(18, thumbnail.width, true);
     bitmap.setInt32(22, -thumbnail.height /* top-down DIB */, true);
     bitmap.setInt16(26, /* ColorPlanes */ 1, true);
@@ -464,6 +464,49 @@ class ImageBuffer {
     bitmap.setUint32(46, /* TotalPalletColors */ 0, true);
     bitmap.setUint32(50, /* ImportantColors */ 0, true);
 
+    bitmap.setUint32(54, /* RedMask */ 0, true);
+    bitmap.setUint32(58, /* GreenMask */ 0, true);
+    bitmap.setUint32(62, /* BlueMask */ 0, true);
+    bitmap.setUint32(66, /* AlphaMask */ 0, true);
+
+    let rx = 0, ry = 0;
+    let gx = 0, gy = 0;
+    let bx = 0, by = 0;
+    let zz = 0, gg = 0;
+
+    if (thumbnail.colorSpace !== 'adobeRgb') {
+      bitmap.setUint8(70, 's'.charCodeAt(0));
+      bitmap.setUint8(71, 'R'.charCodeAt(0));
+      bitmap.setUint8(72, 'G'.charCodeAt(0));
+      bitmap.setUint8(73, 'B'.charCodeAt(0));
+    } else {
+      bitmap.setUint32(70, /* adobeRgb LCS_CALIBRATED_RGB */ 0);
+      rx = Math.round(0.6400 * (1 << 30));
+      ry = Math.round(0.3300 * (1 << 30));
+      gx = Math.round(0.2100 * (1 << 30));
+      gy = Math.round(0.7100 * (1 << 30));
+      bx = Math.round(0.1500 * (1 << 30));
+      by = Math.round(0.0600 * (1 << 30));
+      zz = Math.round(1.0000 * (1 << 30));
+      gg = Math.round(2.1992187 * (1 << 16));
+    }
+
+    // RGB CIEXYZ.
+    bitmap.setUint32( 74, /* R CIEXYZ x */ rx, true);
+    bitmap.setUint32( 78, /* R CIEXYZ y */ ry, true);
+    bitmap.setUint32( 82, /* R CIEXYZ z */ zz, true);
+    bitmap.setUint32( 86, /* G CIEXYZ x */ gx, true);
+    bitmap.setUint32( 90, /* G CIEXYZ y */ gy, true);
+    bitmap.setUint32( 94, /* G CIEXYZ z */ zz, true);
+    bitmap.setUint32( 98, /* B CIEXYZ x */ bx, true);
+    bitmap.setUint32(102, /* B CIEXYZ y */ by, true);
+    bitmap.setUint32(106, /* B CIEXYZ z */ zz, true);
+
+    // RGB gamma.
+    bitmap.setUint32(110, /* R Gamma */ gg, true);
+    bitmap.setUint32(114, /* G Gamma */ gg, true);
+    bitmap.setUint32(118, /* B Gamma */ gg, true);
+
     // Write RGB row pixels in top-down DIB order.
     let output = pixelDataOffset;
     for (let i = 0, y = thumbnail.height; y > 0; --y) {