bugfix(Privacy): Improve iOS Shields standard mode logic (#25499)

* Check for significant text before checking for 3rd party resource

* Add unit test for significant text fix.

ios/brave-ios/Sources/Brave/Frontend/UserContent/UserScripts/Scripts_Dynamic/Scripts/Sandboxed/SelectorsPollerScript.js

@@ -564,6 +564,10 @@ window.__firefox__.execute(function($) {
       return false
     } else if (queryResults.foundFirstPartyResource) {
       return true
+    } else if (showsSignificantText(element)) {
+      // If the subtree HAS a significant amount of text (e.g., it doesn't just says "Advertisement")
+      // it should be unhidden.
+      return true
     } else if (queryResults.foundThirdPartyResource || queryResults.pendingSrcAttributes.size > 0) {
       if (pendingSrcAttributes !== undefined) {
         queryResults.pendingSrcAttributes.forEach((src) => {
@@ -572,12 +576,8 @@ window.__firefox__.execute(function($) {
       }
 
       return false
-    } else {
-      // If the subtree doesn't have a significant amount of text (e.g., it
-      // just says "Advertisement"), then no need to change anything; it should
-      // stay hidden.
-      return showsSignificantText(element)
     }
+    return false
   }
 
   const shouldUnhideElementAsync = async (element) => {

ios/brave-ios/Tests/ClientTests/Resources/html/index.html

@@ -27,7 +27,12 @@ <h1>Test Ads</h1>
 
       <div id="test-ad-3rd-party">
         <img src="http://3rd_party.localhost/image.gif">
-        This element should be always hidden (standard or aggressive mode) because it's a 3rd party ad.
+      </div>
+
+      <div id="test-ad-3rd-party-sig-text">
+        <img src="http://3rd_party.localhost/image.gif">
+        This element should be not be hidden in standard mode because it contains significant amount of text.
+        It should still be hidden in aggressive mode.
       </div>
 
       <div id="test-ad-simple">

ios/brave-ios/Tests/ClientTests/User Scripts/ScriptExecutionTests.swift

@@ -224,7 +224,9 @@ final class ScriptExecutionTests: XCTestCase {
     let initialStandardSelectors = Set([".test-ads-primary-standard div"])
     let initialAggressiveSelectors = Set([".test-ads-primary-aggressive div"])
     let polledAggressiveIds = ["test-ad-aggressive"]
-    let polledStandardIds = ["test-ad-1st-party", "test-ad-3rd-party", "test-ad-simple"]
+    let polledStandardIds = [
+      "test-ad-1st-party", "test-ad-3rd-party", "test-ad-3rd-party-sig-text", "test-ad-simple",
+    ]
     let nestedIds = [
       "test-ad-primary-standard-1st-party", "test-ad-primary-standard-3rd-party",
       "test-ad-primary-aggressive-1st-party", "test-ad-primary-aggressive-3rd-party",
@@ -378,7 +380,10 @@ final class ScriptExecutionTests: XCTestCase {
     )
     XCTAssertEqual(resultsAfterPump?.unhiddenIds.contains("test-ad-1st-party"), true)
     XCTAssertEqual(resultsAfterPump?.hiddenIds.contains("test-ad-aggressive"), true)
+    // hidden because of 3rd party src
     XCTAssertEqual(resultsAfterPump?.hiddenIds.contains("test-ad-3rd-party"), true)
+    // unhidden because it contains significant amount of text
+    XCTAssertEqual(resultsAfterPump?.unhiddenIds.contains("test-ad-3rd-party-sig-text"), true)
     XCTAssertEqual(resultsAfterPump?.hiddenIds.contains("test-ad-simple"), true)
     XCTAssertEqual(
       resultsAfterPump?.hiddenIds.contains("test-ad-primary-aggressive-1st-party"),