Deflake MediaAppIntegrationTest.HandleRawFiles.

File loading and app initialization are interleaved. Because
the test Exif file is small, the codepath taken when file loading
"wins" is taken in about 10% of test runs. RAW files need a delegate
to extract an image preview, and this wasn't being set on this codepath
until app initialization. This could cause the test to attempt to load
the RAW file as a JPEG, resulting in a "decode" error.

To fix, ensure a delegate is set along with the file list to load during
app initialization when that codepath is taken.

Bug: 1152318
Cq-Include-Trybots: luci.chrome.try:linux-chromeos-chrome
Change-Id: I12b37c3f6b6228c621fdb36f975200c74da5d227
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2562921Reviewed-by: Bugs Nash <bugsnash@chromium.org>
Commit-Queue: Trent Apted <tapted@chromium.org>
Cr-Commit-Position: refs/heads/master@{#832600}

chrome/browser/chromeos/web_applications/media_app_integration_browsertest.cc

@@ -214,14 +214,7 @@ IN_PROC_BROWSER_TEST_P(MediaAppIntegrationTest, LoadsPdf) {
 }
 
 // Test that the MediaApp can load RAW files passed on launch params.
-// Disabled on ChromeOS because it fails randomly on linux-chromeos-chrome.
-// See: https://crbug.com/1152318
-#if BUILDFLAG(IS_CHROMEOS_ASH)
-#define MAYBE_HandleRawFiles DISABLED_HandleRawFiles
-#else
-#define MAYBE_HandleRawFiles HandleRawFiles
-#endif
-IN_PROC_BROWSER_TEST_P(MediaAppIntegrationTest, MAYBE_HandleRawFiles) {
+IN_PROC_BROWSER_TEST_P(MediaAppIntegrationTest, HandleRawFiles) {
   WaitForTestSystemAppInstall();
 
   content::WebContents* web_ui;

chromeos/components/media_app_ui/resources/js/media_app.externs.js

@@ -198,6 +198,9 @@ mediaApp.ClientApi.prototype.setDelegate = function(delegate) {};
 
 /**
  * Launch data that can be read by the app when it first loads.
- * @type {{files: mediaApp.AbstractFileList}}
+ * @type {{
+ *     delegate: (mediaApp.ClientApiDelegate | undefined),
+ *     files: mediaApp.AbstractFileList
+ * }}
  */
 window.customLaunchData;

chromeos/components/media_app_ui/resources/js/piex_module_loader.js

@@ -22,9 +22,13 @@ function loadPiex() {
     });
     await loadJs('piex/piex.js.wasm');
     await loadJs('piex_module_scripts.js');
-    await new Promise(resolve => {
-      PiexModule['onRuntimeInitialized'] = resolve;
-    });
+    if (!PiexModule.calledRun) {
+      // In rare cases in tests (<1%), the runtime is already initialized.
+      // Waiting again for onRuntimeInitialized would hang indefinitely.
+      await new Promise(resolve => {
+        PiexModule['onRuntimeInitialized'] = resolve;
+      });
+    }
   }
   if (!_piexLoadPromise) {
     _piexLoadPromise = startLoad();

chromeos/components/media_app_ui/resources/js/receiver.js

@@ -270,7 +270,7 @@ async function loadFiles(fileList) {
     await app.loadFiles(fileList);
   } else {
     // Note we don't await in this case, which may affect b/152729704.
-    window.customLaunchData = {files: fileList};
+    window.customLaunchData.files = fileList;
   }
 }
 
@@ -313,6 +313,7 @@ window.addEventListener('DOMContentLoaded', () => {
 // Ensure that if no files are loaded into the media app there is a default
 // empty file list available.
 window.customLaunchData = {
+  delegate: DELEGATE,
   files: new ReceivedFileList({files: [], currentFileIndex: -1})
 };