[wasm] Bump chrome for testing - linux: 147.0.7727.55, windows: 147.0.7727.56

eng/testing/BrowserVersions.props

@@ -1,8 +1,8 @@
 <Project>
   <PropertyGroup>
-    <linux_ChromeVersion>146.0.7680.80</linux_ChromeVersion>
-    <linux_ChromeRevision>1582197</linux_ChromeRevision>
-    <linux_ChromeBaseSnapshotUrl>https://storage.googleapis.com/chromium-browser-snapshots/Linux_x64/1582214</linux_ChromeBaseSnapshotUrl>
+    <linux_ChromeVersion>147.0.7727.55</linux_ChromeVersion>
+    <linux_ChromeRevision>1596535</linux_ChromeRevision>
+    <linux_ChromeBaseSnapshotUrl>https://storage.googleapis.com/chromium-browser-snapshots/Linux_x64/1596545</linux_ChromeBaseSnapshotUrl>
     <linux_V8Version>14.6.202</linux_V8Version>
     <macos_ChromeVersion>143.0.7499.40</macos_ChromeVersion>
     <macos_ChromeRevision>1536371</macos_ChromeRevision>

src/tasks/WasmBuildTasks/UpdateChromeVersions.cs

@@ -22,6 +22,7 @@ public partial class UpdateChromeVersions : MBU.Task
 {
     private const string s_fetchReleasesUrl = "https://chromiumdash.appspot.com/fetch_releases?channel={0}&num=1";
     private const string s_snapshotBaseUrl = $"https://storage.googleapis.com/chromium-browser-snapshots";
+    private const string s_v8CanaryBaseUrl = "https://storage.googleapis.com/chromium-v8/official/canary";
     private const int s_versionCheckThresholdDays = 1;
 
     private static readonly HttpClient s_httpClient = new();
@@ -195,6 +196,26 @@ private static void UpdateNodeValue(XmlDocument xmlDoc, string nodeName, string
         }
 
         string foundV8Version = await FindV8VersionFromChromeVersion(foundRelease.version).ConfigureAwait(false);
+
+        // Validate that a prebuilt V8 binary exists on the CDN that jsvu uses for downloading.
+        if (!await IsV8BinaryAvailableAsync(osPrefix, foundV8Version).ConfigureAwait(false))
+        {
+            string v8BinaryUrl = GetV8BinaryUrl(osPrefix, foundV8Version);
+            Log.LogWarning($"V8 binary not available at {v8BinaryUrl} — keeping the existing V8 version for {osIdentifier}.");
+
+            // Fall back to the existing V8 version from BrowserVersions.props
+            XmlDocument existingDoc = new XmlDocument();
+            existingDoc.Load(ChromeVersionsPath);
+            string existingV8VersionNodeName = string.Equals(osIdentifier, "linux", StringComparison.OrdinalIgnoreCase)
+                ? "linux_V8Version"
+                : string.Equals(osIdentifier, "windows", StringComparison.OrdinalIgnoreCase)
+                    ? "win_V8Version"
+                    : throw new LogAsErrorException($"Unknown OS identifier '{osIdentifier}' for V8 version fallback");
+            foundV8Version = GetNodeValue(existingDoc, existingV8VersionNodeName);
+            if (string.IsNullOrEmpty(foundV8Version))
+                throw new LogAsErrorException($"V8 binary for {osIdentifier} not available on CDN and no existing version found in {ChromeVersionsPath}");
+        }
+
         ChromeVersionSpec versionSpec = new(os: foundRelease.platform,
                                             channel: Channel,
                                             version: foundRelease.version,
@@ -238,6 +259,36 @@ async Task<string> FindV8VersionFromChromeVersion(string chromeVersion)
         }
     }
 
+    private static string GetV8BinaryUrl(string osPrefix, string v8Version)
+    {
+        string jsvuPlatform = osPrefix switch
+        {
+            "Linux_x64" => "linux64",
+            "Win_x64" => "win32",
+            _ => throw new ArgumentException($"Unknown OS prefix '{osPrefix}' for V8 binary URL")
+        };
+        return $"{s_v8CanaryBaseUrl}/v8-{jsvuPlatform}-rel-{v8Version}.zip";
+    }
+
+    private async Task<bool> IsV8BinaryAvailableAsync(string osPrefix, string v8Version)
+    {
+        string url = GetV8BinaryUrl(osPrefix, v8Version);
+        Log.LogMessage(MessageImportance.Low, $"Checking if V8 binary exists at {url} ...");
+        try
+        {
+            using HttpRequestMessage request = new(HttpMethod.Head, url);
+            using HttpResponseMessage response = await s_httpClient
+                .SendAsync(request, HttpCompletionOption.ResponseHeadersRead)
+                .ConfigureAwait(false);
+            return response.StatusCode == HttpStatusCode.OK;
+        }
+        catch (HttpRequestException hre)
+        {
+            Log.LogWarning($"Failed to check V8 binary availability at {url}: {hre.Message}");
+            return false;
+        }
+    }
+
     private async Task<Stream> GetDownloadFileStreamAsync(string filename, string url)
     {
         string filePath = Path.Combine(IntermediateOutputPath, filename);