Correct a few assumptions in Android Webview code around fenced frames.

- Ensure the frame is the outermost main frame when directing
navigations to the webview code.
- Ensure DocumentHasImage is called only from the outermost main frame.

BUG=1314858

Change-Id: I69cdf6a803f7066603a8c9e631f4213195d3a9e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3631235
Reviewed-by: Bo Liu <boliu@chromium.org>
Reviewed-by: Ken Buchanan <kenrb@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1001169}
NOKEYCHECK=True
GitOrigin-RevId: 436e32b899726d91179ee6604896990bad35b417
diff --git a/java/src/com/android/webview/chromium/WebResourceRequestAdapter.java b/java/src/com/android/webview/chromium/WebResourceRequestAdapter.java
index 0dba191..e0bb9ed 100644
--- a/java/src/com/android/webview/chromium/WebResourceRequestAdapter.java
+++ b/java/src/com/android/webview/chromium/WebResourceRequestAdapter.java
@@ -32,7 +32,7 @@
 
     @Override
     public boolean isForMainFrame() {
-        return mRequest.isMainFrame;
+        return mRequest.isOutermostMainFrame;
     }
 
     @Override