Adds histogram to check whether asset path workaround is used

Bug: 400413041
Change-Id: I761adce0aaf703b3925bee5e87623c4c91d3a9f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6343457
Reviewed-by: Tomasz Wiszkowski <ender@google.com>
Auto-Submit: Alex Mitra <alexmitra@chromium.org>
Reviewed-by: Richard (Torne) Coles <torne@chromium.org>
Commit-Queue: Alex Mitra <alexmitra@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1432147}

android_webview/glue/java/src/com/android/webview/chromium/WebViewChromiumAwInit.java

@@ -85,6 +85,9 @@ public class WebViewChromiumAwInit {
 
     private static final String HTTP_AUTH_DATABASE_FILE = "http_auth.db";
 
+    private static final String ASSET_PATH_WORKAROUND_HISTOGRAM_NAME =
+            "Android.WebView.AssetPathWorkaroundUsed.StartChromiumLocked";
+
     public static class WebViewStartUpDiagnostics {
         private final Object mLock = new Object();
 
@@ -336,7 +339,9 @@ public class WebViewChromiumAwInit {
             // mechanism might not help.
             try {
                 DeviceFormFactor.isTablet();
+                RecordHistogram.recordBooleanHistogram(ASSET_PATH_WORKAROUND_HISTOGRAM_NAME, false);
             } catch (Resources.NotFoundException e) {
+                RecordHistogram.recordBooleanHistogram(ASSET_PATH_WORKAROUND_HISTOGRAM_NAME, true);
                 mFactory.addWebViewAssetPath(context);
             }
 

android_webview/glue/java/src/com/android/webview/chromium/WebViewChromiumFactoryProvider.java

@@ -129,6 +129,9 @@ public class WebViewChromiumFactoryProvider implements WebViewFactoryProvider {
     private static final String SUPPORT_LIB_GLUE_AND_BOUNDARY_INTERFACE_PREFIX =
             "org.chromium.support_lib_";
 
+    private static final String ASSET_PATH_WORKAROUND_HISTOGRAM_NAME =
+            "Android.WebView.AssetPathWorkaroundUsed.FactoryInit";
+
     // This is an ID hardcoded by WebLayer for resources stored in locale splits. See
     // WebLayerImpl.java for more info.
     private static final int SHARED_LIBRARY_MAX_ID = 36;
@@ -433,12 +436,14 @@ public class WebViewChromiumFactoryProvider implements WebViewFactoryProvider {
             int packageId;
             try {
                 packageId = webViewDelegate.getPackageId(ctx.getResources(), resourcePackage);
+                RecordHistogram.recordBooleanHistogram(ASSET_PATH_WORKAROUND_HISTOGRAM_NAME, false);
             } catch (RuntimeException e) {
                 // We failed to find the package ID, which likely means this context's AssetManager
                 // doesn't have WebView loaded in it. This may be because WebViewFactory doesn't add
                 // the package persistently to ResourcesManager and the app's AssetManager has been
                 // recreated. Try adding it again using WebViewDelegate, which does add it
                 // persistently.
+                RecordHistogram.recordBooleanHistogram(ASSET_PATH_WORKAROUND_HISTOGRAM_NAME, true);
                 addWebViewAssetPath(ctx);
                 packageId = webViewDelegate.getPackageId(ctx.getResources(), resourcePackage);
             }

tools/metrics/histograms/metadata/android/histograms.xml

@@ -5778,6 +5778,40 @@ chromium-metrics-reviews@google.com.
   </summary>
 </histogram>
 
+<histogram name="Android.WebView.AssetPathWorkaroundUsed.FactoryInit"
+    enum="Boolean" expires_after="2025-09-11">
+  <owner>alexmitra@chromium.org</owner>
+  <owner>src/android_webview/OWNERS</owner>
+  <summary>
+    In some cases, WebView is unable to find the package ID which usually means
+    that the AssetManager for the Context passed to WebView doesn't have WebView
+    loaded in it. We have a rudimentary workaround for this which is to add
+    WebView's asset path to the Context. Since writing this workaround, we
+    believe we've addressed the underlying problem. Therefore the workaround
+    should no longer be needed. This histogram logs whether the asset path
+    workaround was needed during startup so that we can determine if it's safe
+    to remove. This is logged once during
+    WebViewChromiumFactoryProvider#initialize.
+  </summary>
+</histogram>
+
+<histogram name="Android.WebView.AssetPathWorkaroundUsed.StartChromiumLocked"
+    enum="Boolean" expires_after="2025-09-11">
+  <owner>alexmitra@chromium.org</owner>
+  <owner>src/android_webview/OWNERS</owner>
+  <summary>
+    In some cases, WebView is unable to find its own Resources which usually
+    means that the host app is doing something unsupported with the Context
+    passed to WebView (or with the platform Resources class). We have a
+    rudimentary workaround for this which is to add WebView's asset path to the
+    Context. Since writing this workaround, we believe we've addressed the
+    underlying problem. Therefore the workaround should no longer be needed.
+    This histogram logs whether the asset path workaround was needed during
+    startup so that we can determine if it's safe to remove. This is logged once
+    during WebViewChromiumAwInit#startChromiumLocked.
+  </summary>
+</histogram>
+
 <histogram name="Android.WebView.AwContentsConstructorTime{IsFirst}" units="ms"
     expires_after="2025-09-07">
   <owner>cduvall@chromium.org</owner>